Add tools

20 files changed, 2187 insertions, 0 deletions

diff --git a/tools/gbagfx/.gitignore b/tools/gbagfx/.gitignore
new file mode 100644
index 0000000..dbbb3f0
--- /dev/null
+++ b/tools/gbagfx/.gitignore
@@ -0,0 +1 @@
+gbagfx
diff --git a/tools/gbagfx/LICENSE b/tools/gbagfx/LICENSE
new file mode 100644
index 0000000..b66bf81
--- /dev/null
+++ b/tools/gbagfx/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2015 YamaArashi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/tools/gbagfx/Makefile b/tools/gbagfx/Makefile
new file mode 100644
index 0000000..c10b258
--- /dev/null
+++ b/tools/gbagfx/Makefile
@@ -0,0 +1,18 @@
+CC = gcc
+
+CFLAGS = -Wall -Wextra -Werror -std=c11 -O2 -s -DPNG_SKIP_SETJMP_CHECK
+
+LIBS = -lpng -lz
+
+SRCS = main.c convert_png.c gfx.c jasc_pal.c lz.c rl.c util.c font.c
+
+.PHONY: all clean
+
+all: gbagfx
+	@:
+
+gbagfx: $(SRCS) convert_png.h gfx.h global.h jasc_pal.h lz.h rl.h util.h font.h
+	$(CC) $(CFLAGS) $(SRCS) -o $@ $(LDFLAGS) $(LIBS)
+
+clean:
+	$(RM) gbagfx gbagfx.exe
diff --git a/tools/gbagfx/convert_png.c b/tools/gbagfx/convert_png.c
new file mode 100644
index 0000000..cdfa39a
--- /dev/null
+++ b/tools/gbagfx/convert_png.c
@@ -0,0 +1,254 @@
+// Copyright (c) 2015 YamaArashi
+
+#include <stdio.h>
+#include <setjmp.h>
+#include <png.h>
+#include "global.h"
+#include "convert_png.h"
+#include "gfx.h"
+
+static FILE *PngReadOpen(char *path, png_structp *pngStruct, png_infop *pngInfo)
+{
+    FILE *fp = fopen(path, "rb");
+
+    if (fp == NULL)
+        FATAL_ERROR("Failed to open \"%s\" for reading.\n", path);
+
+    unsigned char sig[8];
+
+    if (fread(sig, 8, 1, fp) != 1)
+        FATAL_ERROR("Failed to read PNG signature from \"%s\".\n", path);
+
+    if (png_sig_cmp(sig, 0, 8))
+        FATAL_ERROR("\"%s\" does not have a valid PNG signature.\n", path);
+
+    png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+
+    if (!png_ptr)
+        FATAL_ERROR("Failed to create PNG read struct.\n");
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+        FATAL_ERROR("Failed to create PNG info struct.\n");
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Failed to init I/O for reading \"%s\".\n", path);
+
+    png_init_io(png_ptr, fp);
+    png_set_sig_bytes(png_ptr, 8);
+    png_read_info(png_ptr, info_ptr);
+
+    *pngStruct = png_ptr;
+    *pngInfo = info_ptr;
+
+    return fp;
+}
+
+static unsigned char *ConvertBitDepth(unsigned char *src, int srcBitDepth, int destBitDepth, int numPixels)
+{
+    // Round the number of bits up to the next 8 and divide by 8 to get the number of bytes.
+    int srcSize = ((numPixels * srcBitDepth + 7) & ~7) / 8;
+    int destSize = ((numPixels * destBitDepth + 7) & ~7) / 8;
+    unsigned char *output = calloc(destSize, 1);
+    unsigned char *dest = output;
+    int i;
+    int j;
+    int destBit = 8 - destBitDepth;
+
+    for (i = 0; i < srcSize; i++)
+    {
+        unsigned char srcByte = src[i];
+
+        for (j = 8 - srcBitDepth; j >= 0; j -= srcBitDepth)
+        {
+            unsigned char pixel = (srcByte >> j) % (1 << srcBitDepth);
+
+            if (pixel >= (1 << destBitDepth))
+                FATAL_ERROR("Image exceeds the maximum color value for a %ibpp image.\n", destBitDepth);
+            *dest |= pixel << destBit;
+            destBit -= destBitDepth;
+            if (destBit < 0)
+            {
+                dest++;
+                destBit = 8 - destBitDepth;
+            }
+        }
+    }
+
+    return output;
+}
+
+void ReadPng(char *path, struct Image *image)
+{
+    png_structp png_ptr;
+    png_infop info_ptr;
+
+    FILE *fp = PngReadOpen(path, &png_ptr, &info_ptr);
+
+    int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
+
+    int color_type = png_get_color_type(png_ptr, info_ptr);
+
+    if (color_type != PNG_COLOR_TYPE_GRAY && color_type != PNG_COLOR_TYPE_PALETTE)
+        FATAL_ERROR("\"%s\" has an unsupported color type.\n", path);
+
+    // Check if the image has a palette so that we can tell if the colors need to be inverted later.
+    // Don't read the palette because it's not needed for now.
+    image->hasPalette = (color_type == PNG_COLOR_TYPE_PALETTE);
+
+    image->width = png_get_image_width(png_ptr, info_ptr);
+    image->height = png_get_image_height(png_ptr, info_ptr);
+
+    int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+    image->pixels = malloc(image->height * rowbytes);
+
+    if (image->pixels == NULL)
+        FATAL_ERROR("Failed to allocate pixel buffer.\n");
+
+    png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
+
+    if (row_pointers == NULL)
+        FATAL_ERROR("Failed to allocate row pointers.\n");
+
+    for (int i = 0; i < image->height; i++)
+        row_pointers[i] = (png_bytep)(image->pixels + (i * rowbytes));
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Error reading from \"%s\".\n", path);
+
+    png_read_image(png_ptr, row_pointers);
+
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+    free(row_pointers);
+    fclose(fp);
+
+    if (bit_depth != image->bitDepth)
+    {
+        unsigned char *src = image->pixels;
+
+        if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 && bit_depth != 8)
+            FATAL_ERROR("Bit depth of image must be 1, 2, 4, or 8.\n");
+        image->pixels = ConvertBitDepth(image->pixels, bit_depth, image->bitDepth, image->width * image->height);
+        free(src);
+        image->bitDepth = bit_depth;
+    }
+}
+
+void ReadPngPalette(char *path, struct Palette *palette)
+{
+    png_structp png_ptr;
+    png_infop info_ptr;
+    png_colorp colors;
+    int numColors;
+
+    FILE *fp = PngReadOpen(path, &png_ptr, &info_ptr);
+
+    if (png_get_color_type(png_ptr, info_ptr) != PNG_COLOR_TYPE_PALETTE)
+        FATAL_ERROR("The image \"%s\" does not contain a palette.\n", path);
+
+    if (png_get_PLTE(png_ptr, info_ptr, &colors, &numColors) != PNG_INFO_PLTE)
+        FATAL_ERROR("Failed to retrieve palette from \"%s\".\n", path);
+
+    if (numColors > 256)
+        FATAL_ERROR("Images with more than 256 colors are not supported.\n");
+
+    palette->numColors = numColors;
+    for (int i = 0; i < numColors; i++) {
+        palette->colors[i].red = colors[i].red;
+        palette->colors[i].green = colors[i].green;
+        palette->colors[i].blue = colors[i].blue;
+    }
+
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+    fclose(fp);
+}
+
+void SetPngPalette(png_structp png_ptr, png_infop info_ptr, struct Palette *palette)
+{
+    png_colorp colors = malloc(palette->numColors * sizeof(png_color));
+
+    if (colors == NULL)
+        FATAL_ERROR("Failed to allocate PNG palette.\n");
+
+    for (int i = 0; i < palette->numColors; i++) {
+        colors[i].red = palette->colors[i].red;
+        colors[i].green = palette->colors[i].green;
+        colors[i].blue = palette->colors[i].blue;
+    }
+
+    png_set_PLTE(png_ptr, info_ptr, colors, palette->numColors);
+
+    free(colors);
+}
+
+void WritePng(char *path, struct Image *image)
+{
+    FILE *fp = fopen(path, "wb");
+
+    if (fp == NULL)
+        FATAL_ERROR("Failed to open \"%s\" for writing.\n", path);
+
+    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+
+    if (!png_ptr)
+        FATAL_ERROR("Failed to create PNG write struct.\n");
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+
+    if (!info_ptr)
+        FATAL_ERROR("Failed to create PNG info struct.\n");
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Failed to init I/O for writing \"%s\".\n", path);
+
+    png_init_io(png_ptr, fp);
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Error writing header for \"%s\".\n", path);
+
+    int color_type = image->hasPalette ? PNG_COLOR_TYPE_PALETTE : PNG_COLOR_TYPE_GRAY;
+
+    png_set_IHDR(png_ptr, info_ptr, image->width, image->height,
+        image->bitDepth, color_type, PNG_INTERLACE_NONE,
+        PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    if (image->hasPalette) {
+        SetPngPalette(png_ptr, info_ptr, &image->palette);
+
+        if (image->hasTransparency) {
+            png_byte trans = 0;
+            png_set_tRNS(png_ptr, info_ptr, &trans, 1, 0);
+        }
+    }
+
+    png_write_info(png_ptr, info_ptr);
+
+    png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
+
+    if (row_pointers == NULL)
+        FATAL_ERROR("Failed to allocate row pointers.\n");
+
+    int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+
+    for (int i = 0; i < image->height; i++)
+        row_pointers[i] = (png_bytep)(image->pixels + (i * rowbytes));
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Error writing \"%s\".\n", path);
+
+    png_write_image(png_ptr, row_pointers);
+
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Error ending write of \"%s\".\n", path);
+
+    png_write_end(png_ptr, NULL);
+
+    fclose(fp);
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+    free(row_pointers);
+}
diff --git a/tools/gbagfx/convert_png.h b/tools/gbagfx/convert_png.h
new file mode 100644
index 0000000..caf081b
--- /dev/null
+++ b/tools/gbagfx/convert_png.h
@@ -0,0 +1,12 @@
+// Copyright (c) 2015 YamaArashi
+
+#ifndef CONVERT_PNG_H
+#define CONVERT_PNG_H
+
+#include "gfx.h"
+
+void ReadPng(char *path, struct Image *image);
+void WritePng(char *path, struct Image *image);
+void ReadPngPalette(char *path, struct Palette *palette);
+
+#endif // CONVERT_PNG_H
diff --git a/tools/gbagfx/font.c b/tools/gbagfx/font.c
new file mode 100644
index 0000000..0dd6fbc
--- /dev/null
+++ b/tools/gbagfx/font.c
@@ -0,0 +1,326 @@
+// Copyright (c) 2015 YamaArashi
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include "global.h"
+#include "font.h"
+#include "gfx.h"
+#include "util.h"
+
+unsigned char gFontPalette[][3] = {
+	{0x90, 0xC8, 0xFF}, // bg (saturated blue that contrasts well with the shadow color)
+	{0x38, 0x38, 0x38}, // fg (dark grey)
+	{0xD8, 0xD8, 0xD8}, // shadow (light grey)
+	{0xFF, 0xFF, 0xFF}  // box (white)
+};
+
+static void ConvertFromLatinFont(unsigned char *src, unsigned char *dest, unsigned int numRows)
+{
+	unsigned int srcPixelsOffset = 0;
+
+	for (unsigned int row = 0; row < numRows; row++) {
+		for (unsigned int column = 0; column < 16; column++) {
+			for (unsigned int glyphTile = 0; glyphTile < 4; glyphTile++) {
+				unsigned int pixelsX = (column * 16) + ((glyphTile & 1) * 8);
+
+				for (unsigned int i = 0; i < 8; i++) {
+					unsigned int pixelsY = (row * 16) + ((glyphTile >> 1) * 8) + i;				
+					unsigned int destPixelsOffset = (pixelsY * 64) + (pixelsX / 4);
+
+					dest[destPixelsOffset] = src[srcPixelsOffset + 1];
+					dest[destPixelsOffset + 1] = src[srcPixelsOffset];
+
+					srcPixelsOffset += 2;
+				}
+			}
+		}
+	}
+}
+
+static void ConvertToLatinFont(unsigned char *src, unsigned char *dest, unsigned int numRows)
+{
+	unsigned int destPixelsOffset = 0;
+
+	for (unsigned int row = 0; row < numRows; row++) {
+		for (unsigned int column = 0; column < 16; column++) {
+			for (unsigned int glyphTile = 0; glyphTile < 4; glyphTile++) {
+				unsigned int pixelsX = (column * 16) + ((glyphTile & 1) * 8);
+
+				for (unsigned int i = 0; i < 8; i++) {
+					unsigned int pixelsY = (row * 16) + ((glyphTile >> 1) * 8) + i;
+					unsigned int srcPixelsOffset = (pixelsY * 64) + (pixelsX / 4);
+
+					dest[destPixelsOffset] = src[srcPixelsOffset + 1];
+					dest[destPixelsOffset + 1] = src[srcPixelsOffset];
+
+					destPixelsOffset += 2;
+				}
+			}
+		}
+	}
+}
+
+static void ConvertFromHalfwidthJapaneseFont(unsigned char *src, unsigned char *dest, unsigned int numRows)
+{
+	for (unsigned int row = 0; row < numRows; row++) {
+		for (unsigned int column = 0; column < 16; column++) {
+			unsigned int glyphIndex = (row * 16) + column;
+
+			for (unsigned int glyphTile = 0; glyphTile < 2; glyphTile++) {
+				unsigned int pixelsX = column * 8;
+				unsigned int srcPixelsOffset = 512 * (glyphIndex >> 4) + 16 * (glyphIndex & 0xF) + 256 * glyphTile;
+
+				for (unsigned int i = 0; i < 8; i++) {
+					unsigned int pixelsY = (row * 16) + (glyphTile * 8) + i;
+					unsigned int destPixelsOffset = (pixelsY * 32) + (pixelsX / 4);
+					
+					dest[destPixelsOffset] = src[srcPixelsOffset + 1];
+					dest[destPixelsOffset + 1] = src[srcPixelsOffset];
+
+					srcPixelsOffset += 2;
+				}
+			}
+		}
+	}
+}
+
+static void ConvertToHalfwidthJapaneseFont(unsigned char *src, unsigned char *dest, unsigned int numRows)
+{
+	for (unsigned int row = 0; row < numRows; row++) {
+		for (unsigned int column = 0; column < 16; column++) {
+			unsigned int glyphIndex = (row * 16) + column;
+
+			for (unsigned int glyphTile = 0; glyphTile < 2; glyphTile++) {
+				unsigned int pixelsX = column * 8;
+				unsigned int destPixelsOffset = 512 * (glyphIndex >> 4) + 16 * (glyphIndex & 0xF) + 256 * glyphTile;
+
+				for (unsigned int i = 0; i < 8; i++) {
+					unsigned int pixelsY = (row * 16) + (glyphTile * 8) + i;
+					unsigned int srcPixelsOffset = (pixelsY * 32) + (pixelsX / 4);
+
+					dest[destPixelsOffset] = src[srcPixelsOffset + 1];
+					dest[destPixelsOffset + 1] = src[srcPixelsOffset];
+
+					destPixelsOffset += 2;
+				}
+			}
+		}
+	}
+}
+
+static void ConvertFromFullwidthJapaneseFont(unsigned char *src, unsigned char *dest, unsigned int numRows)
+{
+	for (unsigned int row = 0; row < numRows; row++) {
+		for (unsigned int column = 0; column < 16; column++) {
+			unsigned int glyphIndex = (row * 16) + column;
+
+			for (unsigned int glyphTile = 0; glyphTile < 4; glyphTile++) {
+				unsigned int pixelsX = (column * 16) + ((glyphTile & 1) * 8);
+				unsigned int srcPixelsOffset = 512 * (glyphIndex >> 3) + 32 * (glyphIndex & 7) + 256 * (glyphTile >> 1) + 16 * (glyphTile & 1);
+
+				for (unsigned int i = 0; i < 8; i++) {
+					unsigned int pixelsY = (row * 16) + ((glyphTile >> 1) * 8) + i;
+					unsigned int destPixelsOffset = (pixelsY * 64) + (pixelsX / 4);
+
+					dest[destPixelsOffset] = src[srcPixelsOffset + 1];
+					dest[destPixelsOffset + 1] = src[srcPixelsOffset];
+
+					srcPixelsOffset += 2;
+				}
+			}
+		}
+	}
+}
+
+static void ConvertToFullwidthJapaneseFont(unsigned char *src, unsigned char *dest, unsigned int numRows)
+{
+	for (unsigned int row = 0; row < numRows; row++) {
+		for (unsigned int column = 0; column < 16; column++) {
+			unsigned int glyphIndex = (row * 16) + column;
+
+			for (unsigned int glyphTile = 0; glyphTile < 4; glyphTile++) {
+				unsigned int pixelsX = (column * 16) + ((glyphTile & 1) * 8);
+				unsigned int destPixelsOffset = 512 * (glyphIndex >> 3) + 32 * (glyphIndex & 7) + 256 * (glyphTile >> 1) + 16 * (glyphTile & 1);
+
+				for (unsigned int i = 0; i < 8; i++) {
+					unsigned int pixelsY = (row * 16) + ((glyphTile >> 1) * 8) + i;
+					unsigned int srcPixelsOffset = (pixelsY * 64) + (pixelsX / 4);
+
+					dest[destPixelsOffset] = src[srcPixelsOffset + 1];
+					dest[destPixelsOffset + 1] = src[srcPixelsOffset];
+
+					destPixelsOffset += 2;
+				}
+			}
+		}
+	}
+}
+
+static void SetFontPalette(struct Image *image)
+{
+	image->hasPalette = true;
+
+	image->palette.numColors = 4;
+
+	for (int i = 0; i < image->palette.numColors; i++) {
+		image->palette.colors[i].red = gFontPalette[i][0];
+		image->palette.colors[i].green = gFontPalette[i][1];
+		image->palette.colors[i].blue = gFontPalette[i][2];
+	}
+
+	image->hasTransparency = false;
+}
+
+void ReadLatinFont(char *path, struct Image *image)
+{
+	int fileSize;
+	unsigned char *buffer = ReadWholeFile(path, &fileSize);
+
+	int numGlyphs = fileSize / 64;
+
+	if (numGlyphs % 16 != 0)
+		FATAL_ERROR("The number of glyphs (%d) is not a multiple of 16.\n", numGlyphs);
+
+	int numRows = numGlyphs / 16;
+
+	image->width = 256;
+	image->height = numRows * 16;
+	image->bitDepth = 2;
+	image->pixels = malloc(fileSize);
+
+	if (image->pixels == NULL)
+		FATAL_ERROR("Failed to allocate memory for font.\n");
+
+	ConvertFromLatinFont(buffer, image->pixels, numRows);
+
+	free(buffer);
+
+	SetFontPalette(image);
+}
+
+void WriteLatinFont(char *path, struct Image *image)
+{
+	if (image->width != 256)
+		FATAL_ERROR("The width of the font image (%d) is not 256.\n", image->width);
+
+	if (image->height % 16 != 0)
+		FATAL_ERROR("The height of the font image (%d) is not a multiple of 16.\n", image->height);
+
+	int numRows = image->height / 16;
+	int bufferSize = numRows * 16 * 64;
+	unsigned char *buffer = malloc(bufferSize);
+
+	if (buffer == NULL)
+		FATAL_ERROR("Failed to allocate memory for font.\n");
+
+	ConvertToLatinFont(image->pixels, buffer, numRows);
+
+	WriteWholeFile(path, buffer, bufferSize);
+
+	free(buffer);
+}
+
+void ReadHalfwidthJapaneseFont(char *path, struct Image *image)
+{
+	int fileSize;
+	unsigned char *buffer = ReadWholeFile(path, &fileSize);
+
+	int glyphSize = 32;
+
+	if (fileSize % glyphSize != 0)
+		FATAL_ERROR("The file size (%d) is not a multiple of %d.\n", fileSize, glyphSize);
+
+	int numGlyphs = fileSize / glyphSize;
+	
+	if (numGlyphs % 16 != 0)
+		FATAL_ERROR("The number of glyphs (%d) is not a multiple of 16.\n", numGlyphs);
+
+	int numRows = numGlyphs / 16;
+
+	image->width = 128;
+	image->height = numRows * 16;
+	image->bitDepth = 2;
+	image->pixels = malloc(fileSize);
+
+	if (image->pixels == NULL)
+		FATAL_ERROR("Failed to allocate memory for font.\n");
+
+	ConvertFromHalfwidthJapaneseFont(buffer, image->pixels, numRows);
+
+	free(buffer);
+
+	SetFontPalette(image);
+}
+
+void WriteHalfwidthJapaneseFont(char *path, struct Image *image)
+{
+	if (image->width != 128)
+		FATAL_ERROR("The width of the font image (%d) is not 128.\n", image->width);
+
+	if (image->height % 16 != 0)
+		FATAL_ERROR("The height of the font image (%d) is not a multiple of 16.\n", image->height);
+
+	int numRows = image->height / 16;
+	int bufferSize = numRows * 16 * 32;
+	unsigned char *buffer = malloc(bufferSize);
+
+	if (buffer == NULL)
+		FATAL_ERROR("Failed to allocate memory for font.\n");
+
+	ConvertToHalfwidthJapaneseFont(image->pixels, buffer, numRows);
+
+	WriteWholeFile(path, buffer, bufferSize);
+
+	free(buffer);
+}
+
+void ReadFullwidthJapaneseFont(char *path, struct Image *image)
+{
+	int fileSize;
+	unsigned char *buffer = ReadWholeFile(path, &fileSize);
+
+	int numGlyphs = fileSize / 64;
+
+	if (numGlyphs % 16 != 0)
+		FATAL_ERROR("The number of glyphs (%d) is not a multiple of 16.\n", numGlyphs);
+
+	int numRows = numGlyphs / 16;
+
+	image->width = 256;
+	image->height = numRows * 16;
+	image->bitDepth = 2;
+	image->pixels = malloc(fileSize);
+
+	if (image->pixels == NULL)
+		FATAL_ERROR("Failed to allocate memory for font.\n");
+
+	ConvertFromFullwidthJapaneseFont(buffer, image->pixels, numRows);
+
+	free(buffer);
+
+	SetFontPalette(image);
+}
+
+void WriteFullwidthJapaneseFont(char *path, struct Image *image)
+{
+	if (image->width != 256)
+		FATAL_ERROR("The width of the font image (%d) is not 256.\n", image->width);
+
+	if (image->height % 16 != 0)
+		FATAL_ERROR("The height of the font image (%d) is not a multiple of 16.\n", image->height);
+
+	int numRows = image->height / 16;
+	int bufferSize = numRows * 16 * 64;
+	unsigned char *buffer = malloc(bufferSize);
+
+	if (buffer == NULL)
+		FATAL_ERROR("Failed to allocate memory for font.\n");
+
+	ConvertToFullwidthJapaneseFont(image->pixels, buffer, numRows);
+
+	WriteWholeFile(path, buffer, bufferSize);
+
+	free(buffer);
+}
diff --git a/tools/gbagfx/font.h b/tools/gbagfx/font.h
new file mode 100644
index 0000000..45086d0
--- /dev/null
+++ b/tools/gbagfx/font.h
@@ -0,0 +1,16 @@
+// Copyright (c) 2015 YamaArashi
+
+#ifndef FONT_H
+#define FONT_H
+
+#include <stdbool.h>
+#include "gfx.h"
+
+void ReadLatinFont(char *path, struct Image *image);
+void WriteLatinFont(char *path, struct Image *image);
+void ReadHalfwidthJapaneseFont(char *path, struct Image *image);
+void WriteHalfwidthJapaneseFont(char *path, struct Image *image);
+void ReadFullwidthJapaneseFont(char *path, struct Image *image);
+void WriteFullwidthJapaneseFont(char *path, struct Image *image);
+
+#endif // FONT_H
diff --git a/tools/gbagfx/gfx.c b/tools/gbagfx/gfx.c
new file mode 100644
index 0000000..f927dee
--- /dev/null
+++ b/tools/gbagfx/gfx.c
@@ -0,0 +1,344 @@
+// Copyright (c) 2015 YamaArashi
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include "global.h"
+#include "gfx.h"
+#include "util.h"
+
+#define GET_GBA_PAL_RED(x)   (((x) >>  0) & 0x1F)
+#define GET_GBA_PAL_GREEN(x) (((x) >>  5) & 0x1F)
+#define GET_GBA_PAL_BLUE(x)  (((x) >> 10) & 0x1F)
+
+#define SET_GBA_PAL(r, g, b) (((b) << 10) | ((g) << 5) | (r))
+
+#define UPCONVERT_BIT_DEPTH(x) (((x) * 255) / 31)
+
+#define DOWNCONVERT_BIT_DEPTH(x) ((x) / 8)
+
+static void AdvanceMetatilePosition(int *subTileX, int *subTileY, int *metatileX, int *metatileY, int metatilesWide, int metatileWidth, int metatileHeight)
+{
+	(*subTileX)++;
+	if (*subTileX == metatileWidth) {
+		*subTileX = 0;
+		(*subTileY)++;
+		if (*subTileY == metatileHeight) {
+			*subTileY = 0;
+			(*metatileX)++;
+			if (*metatileX == metatilesWide) {
+				*metatileX = 0;
+				(*metatileY)++;
+			}
+		}
+	}
+}
+
+static void ConvertFromTiles1Bpp(unsigned char *src, unsigned char *dest, int numTiles, int metatilesWide, int metatileWidth, int metatileHeight, bool invertColors)
+{
+	int subTileX = 0;
+	int subTileY = 0;
+	int metatileX = 0;
+	int metatileY = 0;
+	int pitch = metatilesWide * metatileWidth;
+
+	for (int i = 0; i < numTiles; i++) {
+		for (int j = 0; j < 8; j++) {
+			int destY = (metatileY * metatileHeight + subTileY) * 8 + j;
+			int destX = metatileX * metatileWidth + subTileX;
+			unsigned char srcPixelOctet = *src++;
+			unsigned char *destPixelOctet = &dest[destY * pitch + destX];
+
+			for (int k = 0; k < 8; k++) {
+				*destPixelOctet <<= 1;
+				*destPixelOctet |= (srcPixelOctet & 1) ^ invertColors;
+				srcPixelOctet >>= 1;
+			}
+		}
+
+		AdvanceMetatilePosition(&subTileX, &subTileY, &metatileX, &metatileY, metatilesWide, metatileWidth, metatileHeight);
+	}
+}
+
+static void ConvertFromTiles4Bpp(unsigned char *src, unsigned char *dest, int numTiles, int metatilesWide, int metatileWidth, int metatileHeight, bool invertColors)
+{
+	int subTileX = 0;
+	int subTileY = 0;
+	int metatileX = 0;
+	int metatileY = 0;
+	int pitch = (metatilesWide * metatileWidth) * 4;
+
+	for (int i = 0; i < numTiles; i++) {
+		for (int j = 0; j < 8; j++) {
+			int destY = (metatileY * metatileHeight + subTileY) * 8 + j;
+
+			for (int k = 0; k < 4; k++) {
+				int destX = (metatileX * metatileWidth + subTileX) * 4 + k;
+				unsigned char srcPixelPair = *src++;
+				unsigned char leftPixel = srcPixelPair & 0xF;
+				unsigned char rightPixel = srcPixelPair >> 4;
+
+				if (invertColors) {
+					leftPixel = 15 - leftPixel;
+					rightPixel = 15 - rightPixel;
+				}
+
+				dest[destY * pitch + destX] = (leftPixel << 4) | rightPixel;
+			}
+		}
+
+		AdvanceMetatilePosition(&subTileX, &subTileY, &metatileX, &metatileY, metatilesWide, metatileWidth, metatileHeight);
+	}
+}
+
+static void ConvertFromTiles8Bpp(unsigned char *src, unsigned char *dest, int numTiles, int metatilesWide, int metatileWidth, int metatileHeight, bool invertColors)
+{
+	int subTileX = 0;
+	int subTileY = 0;
+	int metatileX = 0;
+	int metatileY = 0;
+	int pitch = (metatilesWide * metatileWidth) * 8;
+
+	for (int i = 0; i < numTiles; i++) {
+		for (int j = 0; j < 8; j++) {
+			int destY = (metatileY * metatileHeight + subTileY) * 8 + j;
+
+			for (int k = 0; k < 8; k++) {
+				int destX = (metatileX * metatileWidth + subTileX) * 8 + k;
+				unsigned char srcPixel = *src++;
+
+				if (invertColors)
+					srcPixel = 255 - srcPixel;
+
+				dest[destY * pitch + destX] = srcPixel;
+			}
+		}
+
+		AdvanceMetatilePosition(&subTileX, &subTileY, &metatileX, &metatileY, metatilesWide, metatileWidth, metatileHeight);
+	}
+}
+
+static void ConvertToTiles1Bpp(unsigned char *src, unsigned char *dest, int numTiles, int metatilesWide, int metatileWidth, int metatileHeight, bool invertColors)
+{
+	int subTileX = 0;
+	int subTileY = 0;
+	int metatileX = 0;
+	int metatileY = 0;
+	int pitch = metatilesWide * metatileWidth;
+
+	for (int i = 0; i < numTiles; i++) {
+		for (int j = 0; j < 8; j++) {
+			int srcY = (metatileY * metatileHeight + subTileY) * 8 + j;
+			int srcX = metatileX * metatileWidth + subTileX;
+			unsigned char srcPixelOctet = src[srcY * pitch + srcX];
+			unsigned char *destPixelOctet = dest++;
+
+			for (int k = 0; k < 8; k++) {
+				*destPixelOctet <<= 1;
+				*destPixelOctet |= (srcPixelOctet & 1) ^ invertColors;
+				srcPixelOctet >>= 1;
+			}
+		}
+
+		AdvanceMetatilePosition(&subTileX, &subTileY, &metatileX, &metatileY, metatilesWide, metatileWidth, metatileHeight);
+	}
+}
+
+static void ConvertToTiles4Bpp(unsigned char *src, unsigned char *dest, int numTiles, int metatilesWide, int metatileWidth, int metatileHeight, bool invertColors)
+{
+	int subTileX = 0;
+	int subTileY = 0;
+	int metatileX = 0;
+	int metatileY = 0;
+	int pitch = (metatilesWide * metatileWidth) * 4;
+
+	for (int i = 0; i < numTiles; i++) {
+		for (int j = 0; j < 8; j++) {
+			int srcY = (metatileY * metatileHeight + subTileY) * 8 + j;
+
+			for (int k = 0; k < 4; k++) {
+				int srcX = (metatileX * metatileWidth + subTileX) * 4 + k;
+				unsigned char srcPixelPair = src[srcY * pitch + srcX];
+				unsigned char leftPixel = srcPixelPair >> 4;
+				unsigned char rightPixel = srcPixelPair & 0xF;
+
+				if (invertColors) {
+					leftPixel = 15 - leftPixel;
+					rightPixel = 15 - rightPixel;
+				}
+
+				*dest++ = (rightPixel << 4) | leftPixel;
+			}
+		}
+
+		AdvanceMetatilePosition(&subTileX, &subTileY, &metatileX, &metatileY, metatilesWide, metatileWidth, metatileHeight);
+	}
+}
+
+static void ConvertToTiles8Bpp(unsigned char *src, unsigned char *dest, int numTiles, int metatilesWide, int metatileWidth, int metatileHeight, bool invertColors)
+{
+	int subTileX = 0;
+	int subTileY = 0;
+	int metatileX = 0;
+	int metatileY = 0;
+	int pitch = (metatilesWide * metatileWidth) * 8;
+
+	for (int i = 0; i < numTiles; i++) {
+		for (int j = 0; j < 8; j++) {
+			int srcY = (metatileY * metatileHeight + subTileY) * 8 + j;
+
+			for (int k = 0; k < 8; k++) {
+				int srcX = (metatileX * metatileWidth + subTileX) * 8 + k;
+				unsigned char srcPixel = src[srcY * pitch + srcX];
+
+				if (invertColors)
+					srcPixel = 255 - srcPixel;
+
+				*dest++ = srcPixel;
+			}
+		}
+
+		AdvanceMetatilePosition(&subTileX, &subTileY, &metatileX, &metatileY, metatilesWide, metatileWidth, metatileHeight);
+	}
+}
+
+void ReadImage(char *path, int tilesWidth, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors)
+{
+	int tileSize = bitDepth * 8;
+
+	int fileSize;
+	unsigned char *buffer = ReadWholeFile(path, &fileSize);
+
+	int numTiles = fileSize / tileSize;
+
+	int tilesHeight = (numTiles + tilesWidth - 1) / tilesWidth;
+
+	if (tilesWidth % metatileWidth != 0)
+		FATAL_ERROR("The width in tiles (%d) isn't a multiple of the specified metatile width (%d)", tilesWidth, metatileWidth);
+
+	if (tilesHeight % metatileHeight != 0)
+		FATAL_ERROR("The height in tiles (%d) isn't a multiple of the specified metatile height (%d)", tilesHeight, metatileHeight);
+
+	image->width = tilesWidth * 8;
+	image->height = tilesHeight * 8;
+	image->bitDepth = bitDepth;
+	image->pixels = calloc(tilesWidth * tilesHeight, tileSize);
+
+	if (image->pixels == NULL)
+		FATAL_ERROR("Failed to allocate memory for pixels.\n");
+
+	int metatilesWide = tilesWidth / metatileWidth;
+
+	switch (bitDepth) {
+	case 1:
+		ConvertFromTiles1Bpp(buffer, image->pixels, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		break;
+	case 4:
+		ConvertFromTiles4Bpp(buffer, image->pixels, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		break;
+	case 8:
+		ConvertFromTiles8Bpp(buffer, image->pixels, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		break;
+	}
+
+	free(buffer);
+}
+
+void WriteImage(char *path, int numTiles, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors)
+{
+	int tileSize = bitDepth * 8;
+
+	if (image->width % 8 != 0)
+		FATAL_ERROR("The width in pixels (%d) isn't a multiple of 8.\n", image->width);
+
+	if (image->height % 8 != 0)
+		FATAL_ERROR("The height in pixels (%d) isn't a multiple of 8.\n", image->height);
+
+	int tilesWidth = image->width / 8;
+	int tilesHeight = image->height / 8;
+
+	if (tilesWidth % metatileWidth != 0)
+		FATAL_ERROR("The width in tiles (%d) isn't a multiple of the specified metatile width (%d)", tilesWidth, metatileWidth);
+
+	if (tilesHeight % metatileHeight != 0)
+		FATAL_ERROR("The height in tiles (%d) isn't a multiple of the specified metatile height (%d)", tilesHeight, metatileHeight);
+
+	int maxNumTiles = tilesWidth * tilesHeight;
+
+	if (numTiles == 0)
+		numTiles = maxNumTiles;
+	else if (numTiles > maxNumTiles)
+		FATAL_ERROR("The specified number of tiles (%d) is greater than the maximum possible value (%d).\n", numTiles, maxNumTiles);
+
+	int bufferSize = numTiles * tileSize;
+	unsigned char *buffer = malloc(bufferSize);
+
+	if (buffer == NULL)
+		FATAL_ERROR("Failed to allocate memory for pixels.\n");
+
+	int metatilesWide = tilesWidth / metatileWidth;
+
+	switch (bitDepth) {
+	case 1:
+		ConvertToTiles1Bpp(image->pixels, buffer, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		break;
+	case 4:
+		ConvertToTiles4Bpp(image->pixels, buffer, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		break;
+	case 8:
+		ConvertToTiles8Bpp(image->pixels, buffer, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		break;
+	}
+
+	WriteWholeFile(path, buffer, bufferSize);
+
+	free(buffer);
+}
+
+void FreeImage(struct Image *image)
+{
+	free(image->pixels);
+	image->pixels = NULL;
+}
+
+void ReadGbaPalette(char *path, struct Palette *palette)
+{
+	int fileSize;
+	unsigned char *data = ReadWholeFile(path, &fileSize);
+
+	if (fileSize % 2 != 0)
+		FATAL_ERROR("The file size (%d) is not a multiple of 2.\n", fileSize);
+
+	palette->numColors = fileSize / 2;
+
+	for (int i = 0; i < palette->numColors; i++) {
+		uint16_t paletteEntry = (data[i * 2 + 1] << 8) | data[i * 2];
+		palette->colors[i].red = UPCONVERT_BIT_DEPTH(GET_GBA_PAL_RED(paletteEntry));
+		palette->colors[i].green = UPCONVERT_BIT_DEPTH(GET_GBA_PAL_GREEN(paletteEntry));
+		palette->colors[i].blue = UPCONVERT_BIT_DEPTH(GET_GBA_PAL_BLUE(paletteEntry));
+	}
+
+	free(data);
+}
+
+void WriteGbaPalette(char *path, struct Palette *palette)
+{
+	FILE *fp = fopen(path, "wb");
+
+	if (fp == NULL)
+		FATAL_ERROR("Failed to open \"%s\" for writing.\n", path);
+
+	for (int i = 0; i < palette->numColors; i++) {
+		unsigned char red = DOWNCONVERT_BIT_DEPTH(palette->colors[i].red);
+		unsigned char green = DOWNCONVERT_BIT_DEPTH(palette->colors[i].green);
+		unsigned char blue = DOWNCONVERT_BIT_DEPTH(palette->colors[i].blue);
+
+		uint16_t paletteEntry = SET_GBA_PAL(red, green, blue);
+
+		fputc(paletteEntry & 0xFF, fp);
+		fputc(paletteEntry >> 8, fp);
+	}
+
+	fclose(fp);
+}
diff --git a/tools/gbagfx/gfx.h b/tools/gbagfx/gfx.h
new file mode 100644
index 0000000..5355ced
--- /dev/null
+++ b/tools/gbagfx/gfx.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2015 YamaArashi
+
+#ifndef GFX_H
+#define GFX_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+struct Color {
+	unsigned char red;
+	unsigned char green;
+	unsigned char blue;
+};
+
+struct Palette {
+	struct Color colors[256];
+	int numColors;
+};
+
+struct Image {
+	int width;
+	int height;
+	int bitDepth;
+	unsigned char *pixels;
+	bool hasPalette;
+	struct Palette palette;
+	bool hasTransparency;
+};
+
+void ReadImage(char *path, int tilesWidth, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors);
+void WriteImage(char *path, int numTiles, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors);
+void FreeImage(struct Image *image);
+void ReadGbaPalette(char *path, struct Palette *palette);
+void WriteGbaPalette(char *path, struct Palette *palette);
+
+#endif // GFX_H
diff --git a/tools/gbagfx/global.h b/tools/gbagfx/global.h
new file mode 100644
index 0000000..65dd351
--- /dev/null
+++ b/tools/gbagfx/global.h
@@ -0,0 +1,31 @@
+// Copyright (c) 2015 YamaArashi
+
+#ifndef GLOBAL_H
+#define GLOBAL_H
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifdef _MSC_VER
+
+#define FATAL_ERROR(format, ...)          \
+do {                                      \
+    fprintf(stderr, format, __VA_ARGS__); \
+    exit(1);                              \
+} while (0)
+
+#define UNUSED
+
+#else
+
+#define FATAL_ERROR(format, ...)            \
+do {                                        \
+    fprintf(stderr, format, ##__VA_ARGS__); \
+    exit(1);                                \
+} while (0)
+
+#define UNUSED __attribute__((__unused__))
+
+#endif // _MSC_VER
+
+#endif // GLOBAL_H
diff --git a/tools/gbagfx/jasc_pal.c b/tools/gbagfx/jasc_pal.c
new file mode 100644
index 0000000..e5ba9c3
--- /dev/null
+++ b/tools/gbagfx/jasc_pal.c
@@ -0,0 +1,172 @@
+// Copyright (c) 2015 YamaArashi
+
+#include <stdio.h>
+#include <string.h>
+#include "global.h"
+#include "gfx.h"
+#include "util.h"
+
+// Read/write Paint Shop Pro palette files.
+
+// Format of a Paint Shop Pro palette file, line by line:
+// "JASC-PAL\r\n" (signature)
+// "0100\r\n" (version; seems to always be "0100")
+// "<NUMBER_OF_COLORS>\r\n" (number of colors in decimal)
+//
+// <NUMBER_OF_COLORS> times:
+// "<RED> <GREEN> <BLUE>\r\n" (color entry)
+//
+// Each color component is a decimal number from 0 to 255.
+// Examples:
+// Black - "0 0 0\r\n"
+// Blue  - "0 0 255\r\n"
+// Brown - "150 75 0\r\n"
+
+#define MAX_LINE_LENGTH 11
+
+void ReadJascPaletteLine(FILE *fp, char *line)
+{
+    int c;
+    int length = 0;
+
+    for (;;)
+    {
+        c = fgetc(fp);
+
+        if (c == '\r')
+        {
+            c = fgetc(fp);
+
+            if (c != '\n')
+                FATAL_ERROR("CR line endings aren't supported.\n");
+
+            line[length] = 0;
+
+            return;
+        }
+
+        if (c == '\n')
+            FATAL_ERROR("LF line endings aren't supported.\n");
+
+        if (c == EOF)
+            FATAL_ERROR("Unexpected EOF. No CRLF at end of file.\n");
+
+        if (c == 0)
+            FATAL_ERROR("NUL character in file.\n");
+
+        if (length == MAX_LINE_LENGTH)
+        {
+            line[length] = 0;
+            FATAL_ERROR("The line \"%s\" is too long.\n", line);
+        }
+
+        line[length++] = c;
+    }
+}
+
+void ReadJascPalette(char *path, struct Palette *palette)
+{
+    char line[MAX_LINE_LENGTH + 1];
+
+    FILE *fp = fopen(path, "rb");
+
+    if (fp == NULL)
+        FATAL_ERROR("Failed to open JASC-PAL file \"%s\" for reading.\n", path);
+
+    ReadJascPaletteLine(fp, line);
+
+    if (strcmp(line, "JASC-PAL") != 0)
+        FATAL_ERROR("Invalid JASC-PAL signature.\n");
+
+    ReadJascPaletteLine(fp, line);
+
+    if (strcmp(line, "0100") != 0)
+        FATAL_ERROR("Unsuported JASC-PAL version.\n");
+
+    ReadJascPaletteLine(fp, line);
+
+    if (!ParseNumber(line, NULL, 10, &palette->numColors))
+        FATAL_ERROR("Failed to parse number of colors.\n");
+
+    if (palette->numColors < 1 || palette->numColors > 256)
+        FATAL_ERROR("%d is an invalid number of colors. The number of colors must be in the range [1, 256].\n", palette->numColors);
+
+    for (int i = 0; i < palette->numColors; i++)
+    {
+        ReadJascPaletteLine(fp, line);
+
+        char *s = line;
+        char *end;
+
+        int red;
+        int green;
+        int blue;
+
+        if (!ParseNumber(s, &end, 10, &red))
+            FATAL_ERROR("Failed to parse red color component.\n");
+
+        s = end;
+
+        if (*s != ' ')
+            FATAL_ERROR("Expected a space after red color component.\n");
+
+        s++;
+
+        if (*s < '0' || *s > '9')
+            FATAL_ERROR("Expected only a space between red and green color components.\n");
+
+        if (!ParseNumber(s, &end, 10, &green))
+            FATAL_ERROR("Failed to parse green color component.\n");
+
+        s = end;
+
+        if (*s != ' ')
+            FATAL_ERROR("Expected a space after green color component.\n");
+
+        s++;
+
+        if (*s < '0' || *s > '9')
+            FATAL_ERROR("Expected only a space between green and blue color components.\n");
+
+        if (!ParseNumber(s, &end, 10, &blue))
+            FATAL_ERROR("Failed to parse blue color component.\n");
+
+        if (*end != 0)
+            FATAL_ERROR("Garbage after blue color component.\n");
+
+        if (red < 0 || red > 255)
+            FATAL_ERROR("Red color component (%d) is outside the range [0, 255].\n", red);
+
+        if (green < 0 || green > 255)
+            FATAL_ERROR("Green color component (%d) is outside the range [0, 255].\n", green);
+
+        if (blue < 0 || blue > 255)
+            FATAL_ERROR("Blue color component (%d) is outside the range [0, 255].\n", blue);
+
+        palette->colors[i].red = red;
+        palette->colors[i].green = green;
+        palette->colors[i].blue = blue;
+    }
+
+    if (fgetc(fp) != EOF)
+        FATAL_ERROR("Garbage after color data.\n");
+
+    fclose(fp);
+}
+
+void WriteJascPalette(char *path, struct Palette *palette)
+{
+    FILE *fp = fopen(path, "wb");
+
+    fputs("JASC-PAL\r\n", fp);
+    fputs("0100\r\n", fp);
+    fprintf(fp, "%d\r\n", palette->numColors);
+
+    for (int i = 0; i < palette->numColors; i++)
+    {
+        struct Color *color = &palette->colors[i];
+        fprintf(fp, "%d %d %d\r\n", color->red, color->green, color->blue);
+    }
+
+    fclose(fp);
+}
diff --git a/tools/gbagfx/jasc_pal.h b/tools/gbagfx/jasc_pal.h
new file mode 100644
index 0000000..b60b31f
--- /dev/null
+++ b/tools/gbagfx/jasc_pal.h
@@ -0,0 +1,9 @@
+// Copyright (c) 2015 YamaArashi
+
+#ifndef JASC_PAL_H
+#define JASC_PAL_H
+
+void ReadJascPalette(char *path, struct Palette *palette);
+void WriteJascPalette(char *path, struct Palette *palette);
+
+#endif // JASC_PAL_H
diff --git a/tools/gbagfx/lz.c b/tools/gbagfx/lz.c
new file mode 100644
index 0000000..c2ba3e3
--- /dev/null
+++ b/tools/gbagfx/lz.c
@@ -0,0 +1,155 @@
+// Copyright (c) 2015 YamaArashi
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include "global.h"
+#include "lz.h"
+
+unsigned char *LZDecompress(unsigned char *src, int srcSize, int *uncompressedSize)
+{
+	if (srcSize < 4)
+		goto fail;
+
+	int destSize = (src[3] << 16) | (src[2] << 8) | src[1];
+
+	unsigned char *dest = malloc(destSize);
+
+	if (dest == NULL)
+		goto fail;
+
+	int srcPos = 4;
+	int destPos = 0;
+
+	for (;;) {
+		if (srcPos >= srcSize)
+			goto fail;
+
+		unsigned char flags = src[srcPos++];
+
+		for (int i = 0; i < 8; i++) {
+			if (flags & 0x80) {
+				if (srcPos + 1 >= srcSize)
+					goto fail;
+
+				int blockSize = (src[srcPos] >> 4) + 3;
+				int blockDistance = (((src[srcPos] & 0xF) << 8) | src[srcPos + 1]) + 1;
+
+				srcPos += 2;
+
+				int blockPos = destPos - blockDistance;
+
+				// Some Ruby/Sapphire tilesets overflow.
+				if (destPos + blockSize > destSize) {
+					blockSize = destSize - destPos;
+					fprintf(stderr, "Destination buffer overflow.\n");
+				}
+
+				if (blockPos < 0)
+					goto fail;
+
+				for (int j = 0; j < blockSize; j++)
+					dest[destPos++] = dest[blockPos + j];
+			} else {
+				if (srcPos >= srcSize || destPos >= destSize)
+					goto fail;
+
+				dest[destPos++] = src[srcPos++];
+			}
+
+			if (destPos == destSize) {
+				*uncompressedSize = destSize;
+				return dest;
+			}
+
+			flags <<= 1;
+		}
+	}
+
+fail:
+	FATAL_ERROR("Fatal error while decompressing LZ file.\n");
+}
+
+unsigned char *LZCompress(unsigned char *src, int srcSize, int *compressedSize)
+{
+	const int minDistance = 2; // for compatibility with LZ77UnCompVram()
+
+	if (srcSize <= 0)
+		goto fail;
+
+	int worstCaseDestSize = 4 + srcSize + ((srcSize + 7) / 8);
+
+	// Round up to the next multiple of four.
+	worstCaseDestSize = (worstCaseDestSize + 3) & ~3;
+
+	unsigned char *dest = malloc(worstCaseDestSize);
+
+	if (dest == NULL)
+		goto fail;
+
+	// header
+	dest[0] = 0x10; // LZ compression type
+	dest[1] = (unsigned char)srcSize;
+	dest[2] = (unsigned char)(srcSize >> 8);
+	dest[3] = (unsigned char)(srcSize >> 16);
+
+	int srcPos = 0;
+	int destPos = 4;
+
+	for (;;) {
+		unsigned char *flags = &dest[destPos++];
+		*flags = 0;
+
+		for (int i = 0; i < 8; i++) {
+			int bestBlockDistance = 0;
+			int bestBlockSize = 0;
+			int blockDistance = minDistance;
+
+			while (blockDistance <= srcPos && blockDistance <= 0x1000) {
+				int blockStart = srcPos - blockDistance;
+				int blockSize = 0;
+
+				while (blockSize < 18
+				    && srcPos + blockSize < srcSize
+				    && src[blockStart + blockSize] == src[srcPos + blockSize])
+					blockSize++;
+
+				if (blockSize > bestBlockSize) {
+					bestBlockDistance = blockDistance;
+					bestBlockSize = blockSize;
+
+					if (blockSize == 18)
+						break;
+				}
+
+				blockDistance++;
+			}
+
+			if (bestBlockSize >= 3) {
+				*flags |= (0x80 >> i);
+				srcPos += bestBlockSize;
+				bestBlockSize -= 3;
+				bestBlockDistance--;
+				dest[destPos++] = (bestBlockSize << 4) | ((unsigned int)bestBlockDistance >> 8);
+				dest[destPos++] = (unsigned char)bestBlockDistance;
+			} else {
+				dest[destPos++] = src[srcPos++];
+			}
+
+			if (srcPos == srcSize) {
+				// Pad to multiple of 4 bytes.
+				int remainder = destPos % 4;
+
+				if (remainder != 0) {
+					for (int i = 0; i < 4 - remainder; i++)
+						dest[destPos++] = 0;
+				}
+
+				*compressedSize = destPos;
+				return dest;
+			}
+		}
+	}
+
+fail:
+	FATAL_ERROR("Fatal error while compressing LZ file.\n");
+}
diff --git a/tools/gbagfx/lz.h b/tools/gbagfx/lz.h
new file mode 100644
index 0000000..164d622
--- /dev/null
+++ b/tools/gbagfx/lz.h
@@ -0,0 +1,9 @@
+// Copyright (c) 2015 YamaArashi
+
+#ifndef LZ_H
+#define LZ_H
+
+unsigned char *LZDecompress(unsigned char *src, int srcSize, int *uncompressedSize);
+unsigned char *LZCompress(unsigned char *src, int srcSize, int *compressedSize);
+
+#endif // LZ_H
diff --git a/tools/gbagfx/main.c b/tools/gbagfx/main.c
new file mode 100644
index 0000000..86b0afa
--- /dev/null
+++ b/tools/gbagfx/main.c
@@ -0,0 +1,465 @@
+// Copyright (c) 2015 YamaArashi
+
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include "global.h"
+#include "util.h"
+#include "options.h"
+#include "gfx.h"
+#include "convert_png.h"
+#include "jasc_pal.h"
+#include "lz.h"
+#include "rl.h"
+#include "font.h"
+
+struct CommandHandler
+{
+    const char *inputFileExtension;
+    const char *outputFileExtension;
+    void(*function)(char *inputPath, char *outputPath, int argc, char **argv);
+};
+
+void ConvertGbaToPng(char *inputPath, char *outputPath, struct GbaToPngOptions *options)
+{
+    struct Image image;
+
+    if (options->paletteFilePath != NULL)
+    {
+        ReadGbaPalette(options->paletteFilePath, &image.palette);
+        image.hasPalette = true;
+    }
+    else
+    {
+        image.hasPalette = false;
+    }
+
+    ReadImage(inputPath, options->width, options->bitDepth, options->metatileWidth, options->metatileHeight, &image, !image.hasPalette);
+
+    image.hasTransparency = options->hasTransparency;
+
+    WritePng(outputPath, &image);
+
+    FreeImage(&image);
+}
+
+void ConvertPngToGba(char *inputPath, char *outputPath, struct PngToGbaOptions *options)
+{
+    struct Image image;
+
+    image.bitDepth = options->bitDepth;
+
+    ReadPng(inputPath, &image);
+
+    WriteImage(outputPath, options->numTiles, options->bitDepth, options->metatileWidth, options->metatileHeight, &image, !image.hasPalette);
+
+    FreeImage(&image);
+}
+
+void HandleGbaToPngCommand(char *inputPath, char *outputPath, int argc, char **argv)
+{
+    char *inputFileExtension = GetFileExtension(inputPath);
+    struct GbaToPngOptions options;
+    options.paletteFilePath = NULL;
+    options.bitDepth = inputFileExtension[0] - '0';
+    options.hasTransparency = false;
+    options.width = 1;
+    options.metatileWidth = 1;
+    options.metatileHeight = 1;
+
+    for (int i = 3; i < argc; i++)
+    {
+        char *option = argv[i];
+
+        if (strcmp(option, "-palette") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No palette file path following \"-palette\".\n");
+
+            i++;
+
+            options.paletteFilePath = argv[i];
+        }
+        else if (strcmp(option, "-object") == 0)
+        {
+            options.hasTransparency = true;
+        }
+        else if (strcmp(option, "-width") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No width following \"-width\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &options.width))
+                FATAL_ERROR("Failed to parse width.\n");
+
+            if (options.width < 1)
+                FATAL_ERROR("Width must be positive.\n");
+        }
+        else if (strcmp(option, "-mwidth") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No metatile width value following \"-mwidth\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &options.metatileWidth))
+                FATAL_ERROR("Failed to parse metatile width.\n");
+
+            if (options.metatileWidth < 1)
+                FATAL_ERROR("metatile width must be positive.\n");
+        }
+        else if (strcmp(option, "-mheight") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No metatile height value following \"-mheight\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &options.metatileHeight))
+                FATAL_ERROR("Failed to parse metatile height.\n");
+
+            if (options.metatileHeight < 1)
+                FATAL_ERROR("metatile height must be positive.\n");
+        }
+        else
+        {
+            FATAL_ERROR("Unrecognized option \"%s\".\n", option);
+        }
+    }
+
+    if (options.metatileWidth > options.width)
+        options.width = options.metatileWidth;
+
+    ConvertGbaToPng(inputPath, outputPath, &options);
+}
+
+void HandlePngToGbaCommand(char *inputPath, char *outputPath, int argc, char **argv)
+{
+    char *outputFileExtension = GetFileExtension(outputPath);
+    int bitDepth = outputFileExtension[0] - '0';
+    struct PngToGbaOptions options;
+    options.numTiles = 0;
+    options.bitDepth = bitDepth;
+    options.metatileWidth = 1;
+    options.metatileHeight = 1;
+
+    for (int i = 3; i < argc; i++)
+    {
+        char *option = argv[i];
+
+        if (strcmp(option, "-num_tiles") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No number of tiles following \"-num_tiles\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &options.numTiles))
+                FATAL_ERROR("Failed to parse number of tiles.\n");
+
+            if (options.numTiles < 1)
+                FATAL_ERROR("Number of tiles must be positive.\n");
+        }
+        else if (strcmp(option, "-mwidth") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No metatile width value following \"-mwidth\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &options.metatileWidth))
+                FATAL_ERROR("Failed to parse metatile width.\n");
+
+            if (options.metatileWidth < 1)
+                FATAL_ERROR("metatile width must be positive.\n");
+        }
+        else if (strcmp(option, "-mheight") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No metatile height value following \"-mheight\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &options.metatileHeight))
+                FATAL_ERROR("Failed to parse metatile height.\n");
+
+            if (options.metatileHeight < 1)
+                FATAL_ERROR("metatile height must be positive.\n");
+        }
+        else
+        {
+            FATAL_ERROR("Unrecognized option \"%s\".\n", option);
+        }
+    }
+
+    ConvertPngToGba(inputPath, outputPath, &options);
+}
+
+void HandlePngToGbaPaletteCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Palette palette;
+
+    ReadPngPalette(inputPath, &palette);
+    WriteGbaPalette(outputPath, &palette);
+}
+
+void HandleGbaToJascPaletteCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Palette palette;
+
+    ReadGbaPalette(inputPath, &palette);
+    WriteJascPalette(outputPath, &palette);
+}
+
+void HandleJascToGbaPaletteCommand(char *inputPath, char *outputPath, int argc, char **argv)
+{
+    int numColors = 0;
+
+    for (int i = 3; i < argc; i++)
+    {
+        char *option = argv[i];
+
+        if (strcmp(option, "-num_colors") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No number of colors following \"-num_colors\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &numColors))
+                FATAL_ERROR("Failed to parse number of colors.\n");
+
+            if (numColors < 1)
+                FATAL_ERROR("Number of colors must be positive.\n");
+        }
+        else
+        {
+            FATAL_ERROR("Unrecognized option \"%s\".\n", option);
+        }
+    }
+
+    struct Palette palette;
+
+    ReadJascPalette(inputPath, &palette);
+
+    if (numColors != 0)
+        palette.numColors = numColors;
+
+    WriteGbaPalette(outputPath, &palette);
+}
+
+void HandleLatinFontToPngCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Image image;
+
+    ReadLatinFont(inputPath, &image);
+    WritePng(outputPath, &image);
+
+    FreeImage(&image);
+}
+
+void HandlePngToLatinFontCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Image image;
+
+    image.bitDepth = 2;
+
+    ReadPng(inputPath, &image);
+    WriteLatinFont(outputPath, &image);
+
+    FreeImage(&image);
+}
+
+void HandleHalfwidthJapaneseFontToPngCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Image image;
+
+    ReadHalfwidthJapaneseFont(inputPath, &image);
+    WritePng(outputPath, &image);
+
+    FreeImage(&image);
+}
+
+void HandlePngToHalfwidthJapaneseFontCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Image image;
+
+    image.bitDepth = 2;
+
+    ReadPng(inputPath, &image);
+    WriteHalfwidthJapaneseFont(outputPath, &image);
+
+    FreeImage(&image);
+}
+
+void HandleFullwidthJapaneseFontToPngCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Image image;
+
+    ReadFullwidthJapaneseFont(inputPath, &image);
+    WritePng(outputPath, &image);
+
+    FreeImage(&image);
+}
+
+void HandlePngToFullwidthJapaneseFontCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    struct Image image;
+
+    image.bitDepth = 2;
+
+    ReadPng(inputPath, &image);
+    WriteFullwidthJapaneseFont(outputPath, &image);
+
+    FreeImage(&image);
+}
+
+void HandleLZCompressCommand(char *inputPath, char *outputPath, int argc, char **argv)
+{
+    int overflowSize = 0;
+
+    for (int i = 3; i < argc; i++)
+    {
+        char *option = argv[i];
+
+        if (strcmp(option, "-overflow") == 0)
+        {
+            if (i + 1 >= argc)
+                FATAL_ERROR("No size following \"-overflow\".\n");
+
+            i++;
+
+            if (!ParseNumber(argv[i], NULL, 10, &overflowSize))
+                FATAL_ERROR("Failed to parse overflow size.\n");
+
+            if (overflowSize < 1)
+                FATAL_ERROR("Overflow size must be positive.\n");
+        }
+        else
+        {
+            FATAL_ERROR("Unrecognized option \"%s\".\n", option);
+        }
+    }
+
+    // The overflow option allows a quirk in some of Ruby/Sapphire's tilesets
+    // to be reproduced. It works by appending a number of zeros to the data
+    // before compressing it and then amending the LZ header's size field to
+    // reflect the expected size. This will cause an overflow when decompressing
+    // the data.
+
+    int fileSize;
+    unsigned char *buffer = ReadWholeFileZeroPadded(inputPath, &fileSize, overflowSize);
+
+    int compressedSize;
+    unsigned char *compressedData = LZCompress(buffer, fileSize + overflowSize, &compressedSize);
+
+    compressedData[1] = (unsigned char)fileSize;
+    compressedData[2] = (unsigned char)(fileSize >> 8);
+    compressedData[3] = (unsigned char)(fileSize >> 16);
+
+    free(buffer);
+
+    WriteWholeFile(outputPath, compressedData, compressedSize);
+
+    free(compressedData);
+}
+
+void HandleLZDecompressCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    int fileSize;
+    unsigned char *buffer = ReadWholeFile(inputPath, &fileSize);
+
+    int uncompressedSize;
+    unsigned char *uncompressedData = LZDecompress(buffer, fileSize, &uncompressedSize);
+
+    free(buffer);
+
+    WriteWholeFile(outputPath, uncompressedData, uncompressedSize);
+
+    free(uncompressedData);
+}
+
+void HandleRLCompressCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    int fileSize;
+    unsigned char *buffer = ReadWholeFile(inputPath, &fileSize);
+
+    int compressedSize;
+    unsigned char *compressedData = RLCompress(buffer, fileSize, &compressedSize);
+
+    free(buffer);
+
+    WriteWholeFile(outputPath, compressedData, compressedSize);
+
+    free(compressedData);
+}
+
+void HandleRLDecompressCommand(char *inputPath, char *outputPath, int argc UNUSED, char **argv UNUSED)
+{
+    int fileSize;
+    unsigned char *buffer = ReadWholeFile(inputPath, &fileSize);
+
+    int uncompressedSize;
+    unsigned char *uncompressedData = RLDecompress(buffer, fileSize, &uncompressedSize);
+
+    free(buffer);
+
+    WriteWholeFile(outputPath, uncompressedData, uncompressedSize);
+
+    free(uncompressedData);
+}
+
+int main(int argc, char **argv)
+{
+    if (argc < 3)
+        FATAL_ERROR("Usage: gbagfx INPUT_PATH OUTPUT_PATH [options...]\n");
+
+    struct CommandHandler handlers[] =
+    {
+        { "1bpp", "png", HandleGbaToPngCommand },
+        { "4bpp", "png", HandleGbaToPngCommand },
+        { "8bpp", "png", HandleGbaToPngCommand },
+        { "png", "1bpp", HandlePngToGbaCommand },
+        { "png", "4bpp", HandlePngToGbaCommand },
+        { "png", "8bpp", HandlePngToGbaCommand },
+        { "png", "gbapal", HandlePngToGbaPaletteCommand },
+        { "gbapal", "pal", HandleGbaToJascPaletteCommand },
+        { "pal", "gbapal", HandleJascToGbaPaletteCommand },
+        { "latfont", "png", HandleLatinFontToPngCommand },
+        { "png", "latfont", HandlePngToLatinFontCommand },
+        { "hwjpnfont", "png", HandleHalfwidthJapaneseFontToPngCommand },
+        { "png", "hwjpnfont", HandlePngToHalfwidthJapaneseFontCommand },
+        { "fwjpnfont", "png", HandleFullwidthJapaneseFontToPngCommand },
+        { "png", "fwjpnfont", HandlePngToFullwidthJapaneseFontCommand },
+        { NULL, "lz", HandleLZCompressCommand },
+        { "lz", NULL, HandleLZDecompressCommand },
+        { NULL, "rl", HandleRLCompressCommand },
+        { "rl", NULL, HandleRLDecompressCommand },
+        { NULL, NULL, NULL }
+    };
+
+    char *inputPath = argv[1];
+    char *outputPath = argv[2];
+    char *inputFileExtension = GetFileExtension(inputPath);
+    char *outputFileExtension = GetFileExtension(outputPath);
+
+    if (inputFileExtension == NULL)
+        FATAL_ERROR("Input file \"%s\" has no extension.\n", inputPath);
+
+    if (outputFileExtension == NULL)
+        FATAL_ERROR("Output file \"%s\" has no extension.\n", outputPath);
+
+    for (int i = 0; handlers[i].function != NULL; i++)
+    {
+        if ((handlers[i].inputFileExtension == NULL || strcmp(handlers[i].inputFileExtension, inputFileExtension) == 0)
+            && (handlers[i].outputFileExtension == NULL || strcmp(handlers[i].outputFileExtension, outputFileExtension) == 0))
+        {
+            handlers[i].function(inputPath, outputPath, argc, argv);
+            return 0;
+        }
+    }
+
+    FATAL_ERROR("Don't know how to convert \"%s\" to \"%s\".\n", inputPath, outputPath);
+}
diff --git a/tools/gbagfx/options.h b/tools/gbagfx/options.h
new file mode 100755
index 0000000..2ff3967
--- /dev/null
+++ b/tools/gbagfx/options.h
@@ -0,0 +1,24 @@
+// Copyright (c) 2018 huderlem
+
+#ifndef OPTIONS_H
+#define OPTIONS_H
+
+#include <stdbool.h>
+
+struct GbaToPngOptions {
+    char *paletteFilePath;
+    int bitDepth;
+    bool hasTransparency;
+    int width;
+    int metatileWidth;
+    int metatileHeight;
+};
+
+struct PngToGbaOptions {
+    int numTiles;
+    int bitDepth;
+    int metatileWidth;
+    int metatileHeight;
+};
+
+#endif // OPTIONS_H
diff --git a/tools/gbagfx/rl.c b/tools/gbagfx/rl.c
new file mode 100644
index 0000000..968c934
--- /dev/null
+++ b/tools/gbagfx/rl.c
@@ -0,0 +1,149 @@
+// Copyright (c) 2016 YamaArashi
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include "global.h"
+#include "rl.h"
+
+unsigned char *RLDecompress(unsigned char *src, int srcSize, int *uncompressedSize)
+{
+    if (srcSize < 4)
+        goto fail;
+
+    int destSize = (src[3] << 16) | (src[2] << 8) | src[1];
+
+    unsigned char *dest = malloc(destSize);
+
+    if (dest == NULL)
+        goto fail;
+
+    int srcPos = 4;
+    int destPos = 0;
+
+    for (;;)
+    {
+        if (srcPos >= srcSize)
+            goto fail;
+
+        unsigned char flags = src[srcPos++];
+        bool compressed = ((flags & 0x80) != 0);
+
+        if (compressed)
+        {
+            int length = (flags & 0x7F) + 3;
+            unsigned char data = src[srcPos++];
+
+            if (destPos + length > destSize)
+                goto fail;
+
+            for (int i = 0; i < length; i++)
+                dest[destPos++] = data;
+        }
+        else
+        {
+            int length = (flags & 0x7F) + 1;
+
+            if (destPos + length > destSize)
+                goto fail;
+
+            for (int i = 0; i < length; i++)
+                dest[destPos++] = src[srcPos++];
+        }
+
+        if (destPos == destSize)
+        {
+            *uncompressedSize = destSize;
+            return dest;
+        }
+    }
+
+fail:
+    FATAL_ERROR("Fatal error while decompressing RL file.\n");
+}
+
+unsigned char *RLCompress(unsigned char *src, int srcSize, int *compressedSize)
+{
+    if (srcSize <= 0)
+        goto fail;
+
+    int worstCaseDestSize = 4 + srcSize * 2;
+
+    // Round up to the next multiple of four.
+    worstCaseDestSize = (worstCaseDestSize + 3) & ~3;
+
+    unsigned char *dest = malloc(worstCaseDestSize);
+
+    if (dest == NULL)
+        goto fail;
+
+    // header
+    dest[0] = 0x30; // RL compression type
+    dest[1] = (unsigned char)srcSize;
+    dest[2] = (unsigned char)(srcSize >> 8);
+    dest[3] = (unsigned char)(srcSize >> 16);
+
+    int srcPos = 0;
+    int destPos = 4;
+
+    for (;;)
+    {
+        bool compress = false;
+        int uncompressedStart = srcPos;
+        int uncompressedLength = 0;
+
+        while (srcPos < srcSize && uncompressedLength < (0x7F + 1))
+        {
+            compress = (srcPos + 2 < srcSize && src[srcPos] == src[srcPos + 1] && src[srcPos] == src[srcPos + 2]);
+
+            if (compress)
+                break;
+
+            srcPos++;
+            uncompressedLength++;
+        }
+        
+        if (uncompressedLength > 0)
+        {
+            dest[destPos++] = uncompressedLength - 1;
+
+            for (int i = 0; i < uncompressedLength; i++)
+                dest[destPos++] = src[uncompressedStart + i];
+        }
+
+        if (compress)
+        {
+            unsigned char data = src[srcPos];
+            int compressedLength = 0;
+
+            while (compressedLength < (0x7F + 3)
+                && srcPos + compressedLength < srcSize
+                && src[srcPos + compressedLength] == data)
+            {
+                compressedLength++;
+            }
+
+            dest[destPos++] = 0x80 | (compressedLength - 3);
+            dest[destPos++] = data;
+
+            srcPos += compressedLength;
+        }
+
+        if (srcPos == srcSize)
+        {
+            // Pad to multiple of 4 bytes.
+            int remainder = destPos % 4;
+
+            if (remainder != 0)
+            {
+                for (int i = 0; i < 4 - remainder; i++)
+                    dest[destPos++] = 0;
+            }
+
+            *compressedSize = destPos;
+            return dest;
+        }
+    }
+
+fail:
+    FATAL_ERROR("Fatal error while compressing RL file.\n");
+}
diff --git a/tools/gbagfx/rl.h b/tools/gbagfx/rl.h
new file mode 100644
index 0000000..02ad8d6
--- /dev/null
+++ b/tools/gbagfx/rl.h
@@ -0,0 +1,9 @@
+// Copyright (c) 2016 YamaArashi
+
+#ifndef RL_H
+#define RL_H
+
+unsigned char *RLDecompress(unsigned char *src, int srcSize, int *uncompressedSize);
+unsigned char *RLCompress(unsigned char *src, int srcSize, int *compressedSize);
+
+#endif // RL_H
diff --git a/tools/gbagfx/util.c b/tools/gbagfx/util.c
new file mode 100644
index 0000000..87abeb3
--- /dev/null
+++ b/tools/gbagfx/util.c
@@ -0,0 +1,124 @@
+// Copyright (c) 2015 YamaArashi
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <limits.h>
+#include "global.h"
+#include "util.h"
+
+bool ParseNumber(char *s, char **end, int radix, int *intValue)
+{
+	char *localEnd;
+
+	if (end == NULL)
+		end = &localEnd;
+
+	errno = 0;
+
+	const long longValue = strtol(s, end, radix);
+
+	if (*end == s)
+		return false; // not a number
+
+	if ((longValue == LONG_MIN || longValue == LONG_MAX) && errno == ERANGE)
+		return false;
+
+	if (longValue > INT_MAX)
+		return false;
+
+	if (longValue < INT_MIN)
+		return false;
+
+	*intValue = (int)longValue;
+
+	return true;
+}
+
+char *GetFileExtension(char *path)
+{
+	char *extension = path;
+
+	while (*extension != 0)
+		extension++;
+
+	while (extension > path && *extension != '.')
+		extension--;
+
+	if (extension == path)
+		return NULL;
+
+	extension++;
+
+	if (*extension == 0)
+		return NULL;
+
+	return extension;
+}
+
+unsigned char *ReadWholeFile(char *path, int *size)
+{
+	FILE *fp = fopen(path, "rb");
+
+	if (fp == NULL)
+		FATAL_ERROR("Failed to open \"%s\" for reading.\n", path);
+
+	fseek(fp, 0, SEEK_END);
+
+	*size = ftell(fp);
+
+	unsigned char *buffer = malloc(*size);
+
+	if (buffer == NULL)
+		FATAL_ERROR("Failed to allocate memory for reading \"%s\".\n", path);
+
+	rewind(fp);
+
+	if (fread(buffer, *size, 1, fp) != 1)
+		FATAL_ERROR("Failed to read \"%s\".\n", path);
+
+	fclose(fp);
+
+	return buffer;
+}
+
+unsigned char *ReadWholeFileZeroPadded(char *path, int *size, int padAmount)
+{
+	FILE *fp = fopen(path, "rb");
+
+	if (fp == NULL)
+		FATAL_ERROR("Failed to open \"%s\" for reading.\n", path);
+
+	fseek(fp, 0, SEEK_END);
+
+	*size = ftell(fp);
+
+	unsigned char *buffer = calloc(*size + padAmount, 1);
+
+	if (buffer == NULL)
+		FATAL_ERROR("Failed to allocate memory for reading \"%s\".\n", path);
+
+	rewind(fp);
+
+	if (fread(buffer, *size, 1, fp) != 1)
+		FATAL_ERROR("Failed to read \"%s\".\n", path);
+
+	fclose(fp);
+
+	return buffer;
+}
+
+void WriteWholeFile(char *path, void *buffer, int bufferSize)
+{
+	FILE *fp = fopen(path, "wb");
+
+	if (fp == NULL)
+		FATAL_ERROR("Failed to open \"%s\" for writing.\n", path);
+
+	if (fwrite(buffer, bufferSize, 1, fp) != 1)
+		FATAL_ERROR("Failed to write to \"%s\".\n", path);
+
+	fclose(fp);
+}
diff --git a/tools/gbagfx/util.h b/tools/gbagfx/util.h
new file mode 100644
index 0000000..6d7a9c2
--- /dev/null
+++ b/tools/gbagfx/util.h
@@ -0,0 +1,14 @@
+// Copyright (c) 2015 YamaArashi
+
+#ifndef UTIL_H
+#define UTIL_H
+
+#include <stdbool.h>
+
+bool ParseNumber(char *s, char **end, int radix, int *intValue);
+char *GetFileExtension(char *path);
+unsigned char *ReadWholeFile(char *path, int *size);
+unsigned char *ReadWholeFileZeroPadded(char *path, int *size, int padAmount);
+void WriteWholeFile(char *path, void *buffer, int bufferSize);
+
+#endif // UTIL_H