add png -> gbapal conversion

3 files changed, 150 insertions, 97 deletions

diff --git a/tools/gbagfx/convert_png.c b/tools/gbagfx/convert_png.c
index f6a30804a..37904318c 100644
--- a/tools/gbagfx/convert_png.c
+++ b/tools/gbagfx/convert_png.c
@@ -7,163 +7,206 @@
 #include "convert_png.h"
 #include "gfx.h"
 
-void ReadPng(char *path, struct Image *image)
+static FILE *PngReadOpen(char *path, png_structp *pngStruct, png_infop *pngInfo)
 {
-	FILE *fp = fopen(path, "rb");
+    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 (fp == NULL)
-		FATAL_ERROR("Failed to open \"%s\" for reading.\n", path);
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Failed to init I/O for reading \"%s\".\n", path);
 
-	unsigned char sig[8];
+    png_init_io(png_ptr, fp);
+    png_set_sig_bytes(png_ptr, 8);
+    png_read_info(png_ptr, info_ptr);
 
-	if (fread(sig, 8, 1, fp) != 1)
-		FATAL_ERROR("Failed to read PNG signature from \"%s\".\n", path);
+    *pngStruct = png_ptr;
+    *pngInfo = info_ptr;
 
-	if (png_sig_cmp(sig, 0, 8))
-		FATAL_ERROR("\"%s\" does not have a valid PNG signature.\n", path);
+    return fp;
+}
+
+void ReadPng(char *path, struct Image *image)
+{
+    png_structp png_ptr;
+    png_infop info_ptr;
+
+    FILE *fp = PngReadOpen(path, &png_ptr, &info_ptr);
 
-	png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
 
-	if (!png_ptr)
-		FATAL_ERROR("Failed to create PNG read struct.\n");
+    if (bit_depth != image->bitDepth)
+        FATAL_ERROR("\"%s\" has a bit depth of %d, but the expected bit depth is %d.\n", path, bit_depth, image->bitDepth);
 
-	png_infop info_ptr = png_create_info_struct(png_ptr);
+    int color_type = png_get_color_type(png_ptr, info_ptr);
 
-	if (!info_ptr)
-		FATAL_ERROR("Failed to create PNG info struct.\n");
+    if (color_type != PNG_COLOR_TYPE_GRAY && color_type != PNG_COLOR_TYPE_PALETTE)
+        FATAL_ERROR("\"%s\" has an unsupported color type.\n", path);
 
-	if (setjmp(png_jmpbuf(png_ptr)))
-		FATAL_ERROR("Failed to init I/O for reading \"%s\".\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);
 
-	png_init_io(png_ptr, fp);
-	png_set_sig_bytes(png_ptr, 8);
-	png_read_info(png_ptr, info_ptr);
+    image->width = png_get_image_width(png_ptr, info_ptr);
+    image->height = png_get_image_height(png_ptr, info_ptr);
 
-	int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
+    int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
 
-	if (bit_depth != image->bitDepth)
-		FATAL_ERROR("\"%s\" has a bit depth of %d, but the expected bit depth is %d.\n", path, bit_depth, image->bitDepth);
+    image->pixels = malloc(image->height * rowbytes);
 
-	int color_type = png_get_color_type(png_ptr, info_ptr);
+    if (image->pixels == NULL)
+        FATAL_ERROR("Failed to allocate pixel buffer.\n");
 
-	if (color_type != PNG_COLOR_TYPE_GRAY && color_type != PNG_COLOR_TYPE_PALETTE)
-		FATAL_ERROR("\"%s\" has an unsupported color type.\n", path);
+    png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
 
-	// 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);
+    if (row_pointers == NULL)
+        FATAL_ERROR("Failed to allocate row pointers.\n");
 
-	image->width = png_get_image_width(png_ptr, info_ptr);
-	image->height = png_get_image_height(png_ptr, info_ptr);
+    for (int i = 0; i < image->height; i++)
+        row_pointers[i] = (png_bytep)(image->pixels + (i * rowbytes));
 
-	int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Error reading from \"%s\".\n", path);
 
-	image->pixels = malloc(image->height * rowbytes);
+    png_read_image(png_ptr, row_pointers);
 
-	if (image->pixels == NULL)
-		FATAL_ERROR("Failed to allocate pixel buffer.\n");
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+
+    free(row_pointers);
+    fclose(fp);
+}
+
+void ReadPngPalette(char *path, struct Palette *palette)
+{
+    png_structp png_ptr;
+    png_infop info_ptr;
+    png_colorp colors;
+    int numColors;
 
-	png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
+    FILE *fp = PngReadOpen(path, &png_ptr, &info_ptr);
 
-	if (row_pointers == NULL)
-		FATAL_ERROR("Failed to allocate row pointers.\n");
+    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);
 
-	for (int i = 0; i < image->height; i++)
-		row_pointers[i] = (png_bytep)(image->pixels + (i * rowbytes));
+    if (png_get_PLTE(png_ptr, info_ptr, &colors, &numColors) != PNG_INFO_PLTE)
+        FATAL_ERROR("Failed to retrieve palette from \"%s\".\n", path);
 
-	if (setjmp(png_jmpbuf(png_ptr)))
-		FATAL_ERROR("Error reading from \"%s\".\n", path);
+    if (numColors > 256)
+        FATAL_ERROR("Images with more than 256 colors are not supported.\n");
 
-	png_read_image(png_ptr, row_pointers);
+    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);
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 
-	free(row_pointers);
-	fclose(fp);
+    fclose(fp);
 }
 
 void SetPngPalette(png_structp png_ptr, png_infop info_ptr, struct Palette *palette)
 {
-	png_colorp colors = malloc(palette->numColors * sizeof(png_color));
+    png_colorp colors = malloc(palette->numColors * sizeof(png_color));
 
-	if (colors == NULL)
-		FATAL_ERROR("Failed to allocate PNG palette.\n");
+    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;
-	}
+    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);
+    png_set_PLTE(png_ptr, info_ptr, colors, palette->numColors);
 
-	free(colors);
+    free(colors);
 }
 
 void WritePng(char *path, struct Image *image)
 {
-	FILE *fp = fopen(path, "wb");
+    FILE *fp = fopen(path, "wb");
 
-	if (fp == NULL)
-		FATAL_ERROR("Failed to open \"%s\" for writing.\n", path);
+    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);
+    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");
+    if (!png_ptr)
+        FATAL_ERROR("Failed to create PNG write struct.\n");
 
-	png_infop info_ptr = png_create_info_struct(png_ptr);
+    png_infop info_ptr = png_create_info_struct(png_ptr);
 
-	if (!info_ptr)
-		FATAL_ERROR("Failed to create PNG info struct.\n");
+    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);
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Failed to init I/O for writing \"%s\".\n", path);
 
-	png_init_io(png_ptr, fp);
+    png_init_io(png_ptr, fp);
 
-	if (setjmp(png_jmpbuf(png_ptr)))
-		FATAL_ERROR("Error writing header for \"%s\".\n", path);
+    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;
+    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);
+    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->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);
-		}
-	}
+        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_write_info(png_ptr, info_ptr);
 
-	png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
+    png_bytepp row_pointers = malloc(image->height * sizeof(png_bytep));
 
-	if (row_pointers == NULL)
-		FATAL_ERROR("Failed to allocate row pointers.\n");
+    if (row_pointers == NULL)
+        FATAL_ERROR("Failed to allocate row pointers.\n");
 
-	int rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+    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));
+    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);
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Error writing \"%s\".\n", path);
 
-	png_write_image(png_ptr, row_pointers);
+    png_write_image(png_ptr, row_pointers);
 
-	if (setjmp(png_jmpbuf(png_ptr)))
-		FATAL_ERROR("Error ending write of \"%s\".\n", path);
+    if (setjmp(png_jmpbuf(png_ptr)))
+        FATAL_ERROR("Error ending write of \"%s\".\n", path);
 
-	png_write_end(png_ptr, NULL);
+    png_write_end(png_ptr, NULL);
 
-	fclose(fp);
+    fclose(fp);
 
-	png_destroy_write_struct(&png_ptr, &info_ptr);
-	free(row_pointers);
+    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
index 55d3d6942..caf081b73 100644
--- a/tools/gbagfx/convert_png.h
+++ b/tools/gbagfx/convert_png.h
@@ -7,5 +7,6 @@
 
 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/main.c b/tools/gbagfx/main.c
index 37d3441fe..97db60e84 100644
--- a/tools/gbagfx/main.c
+++ b/tools/gbagfx/main.c
@@ -134,6 +134,14 @@ void HandlePngToGbaCommand(char *inputPath, char *outputPath, int argc, char **a
     ConvertPngToGba(inputPath, outputPath, numTiles, bitDepth);
 }
 
+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;
@@ -353,6 +361,7 @@ int main(int argc, char **argv)
         { "png", "1bpp", HandlePngToGbaCommand },
         { "png", "4bpp", HandlePngToGbaCommand },
         { "png", "8bpp", HandlePngToGbaCommand },
+        { "png", "gbapal", HandlePngToGbaPaletteCommand },
         { "gbapal", "pal", HandleGbaToJascPaletteCommand },
         { "pal", "gbapal", HandleJascToGbaPaletteCommand },
         { "latfont", "png", HandleLatinFontToPngCommand },