Util: Preliminary palette support

include/mgba-util/image.h

@@ -77,6 +77,7 @@ enum mColorFormat {
 	mCOLOR_RGB8   = 0x10000,
 	mCOLOR_BGR8   = 0x20000,
 	mCOLOR_L8     = 0x40000,
+	mCOLOR_PAL8   = 0x80000,
 
 	mCOLOR_ANY    = -1
 };
@@ -91,10 +92,12 @@ enum mColorFormat {
 
 struct mImage {
 	void* data;
+	uint32_t* palette;
 	unsigned width;
 	unsigned height;
 	unsigned stride;
 	unsigned depth;
+	unsigned palSize;
 	enum mColorFormat format;
 };
 
@@ -146,6 +149,7 @@ static inline unsigned mColorFormatBytes(enum mColorFormat format) {
 	case mCOLOR_BGR8:
 		return 3;
 	case mCOLOR_L8:
+	case mCOLOR_PAL8:
 		return 1;
 	case mCOLOR_ANY:
 		break;
@@ -175,6 +179,7 @@ static inline bool mColorFormatHasAlpha(enum mColorFormat format) {
 	case mCOLOR_ABGR5:
 	case mCOLOR_RGBA5:
 	case mCOLOR_BGRA5:
+	case mCOLOR_PAL8:
 		return true;
 	case mCOLOR_ANY:
 		break;

src/util/image.c

@@ -135,17 +135,51 @@ static struct mImage* mImageLoadPNG(struct VFile* vf) {
 	case 1:
 		if (png_get_color_type(png, info) == PNG_COLOR_TYPE_GRAY) {
 			image->format = mCOLOR_L8;
-			image->depth = 1;
+		} else {
-			image->data = malloc(width * height);
+			png_colorp palette;
-			if (!PNGReadPixels8(png, info, image->data, width, height, width)) {
+			png_bytep trns;
-				free(image->data);
+			int count;
-				free(image);
+			int trnsCount = 0;
-				PNGReadClose(png, info, end);
+			image->format = mCOLOR_PAL8;
+			if (png_get_PLTE(png, info, &palette, &count) == 0) {
 				return NULL;
 			}
-			break;
+			if (count > 256) {
+				count = 256;
+#ifndef NDEBUG
+				abort();
+#endif
+			}
+			image->palette = malloc(1024);
+			image->palSize = count;
+			png_get_tRNS(png, info, &trns, &trnsCount, NULL);
+
+			int i;
+			for (i = 0; i < count; ++i) {
+				uint32_t color = palette[i].red << 16;
+				color |= palette[i].green << 8;
+				color |= palette[i].blue;
+
+				if (i < trnsCount) {
+					color |= trns[i] << 24;
+				} else {
+					color |= 0xFF000000;
+				}
+				image->palette[i] = color;
+			}
 		}
-		// Fall through
+		image->depth = 1;
+		image->data = malloc(width * height);
+		if (!PNGReadPixels8(png, info, image->data, width, height, width)) {
+			if (image->palette) {
+				free(image->palette);
+			}
+			free(image->data);
+			free(image);
+			PNGReadClose(png, info, end);
+			return NULL;
+		}
+		break;
 	default:
 		// Not supported yet
 		free(image);
@@ -169,6 +203,10 @@ struct mImage* mImageLoadVF(struct VFile* vf) {
 }
 
 struct mImage* mImageConvertToFormat(const struct mImage* image, enum mColorFormat format) {
+	if (format == mCOLOR_PAL8) {
+		// Quantization shouldn't be handled here
+		return NULL;
+	}
 	struct mImage* newImage = calloc(1, sizeof(*newImage));
 	newImage->width = image->width;
 	newImage->height = image->height;
@@ -186,20 +224,36 @@ struct mImage* mImageConvertToFormat(const struct mImage* image, enum mColorForm
 
 	// TODO: Implement more specializations, e.g. alpha narrowing/widening, channel swapping
 	size_t x, y;
-	for (y = 0; y < newImage->height; ++y) {
+	if (image->format == mCOLOR_PAL8) {
-		uintptr_t src = (uintptr_t) ROW(image, y);
+		for (y = 0; y < newImage->height; ++y) {
-		uintptr_t dst = (uintptr_t) ROW(newImage, y);
+			uintptr_t src = (uintptr_t) ROW(image, y);
-		for (x = 0; x < newImage->width; ++x, src += image->depth, dst += newImage->depth) {
+			uintptr_t dst = (uintptr_t) ROW(newImage, y);
-			uint32_t color;
+			for (x = 0; x < newImage->width; ++x, src += image->depth, dst += newImage->depth) {
-			GET_PIXEL(color, src, image->depth);
+				uint32_t color;
-			color = mColorConvert(color, image->format, format);
+				GET_PIXEL(color, src, image->depth);
-			PUT_PIXEL(color, dst, newImage->depth);
+				color = image->palette[color];
+				PUT_PIXEL(color, dst, newImage->depth);
+			}
+		}
+	} else {
+		for (y = 0; y < newImage->height; ++y) {
+			uintptr_t src = (uintptr_t) ROW(image, y);
+			uintptr_t dst = (uintptr_t) ROW(newImage, y);
+			for (x = 0; x < newImage->width; ++x, src += image->depth, dst += newImage->depth) {
+				uint32_t color;
+				GET_PIXEL(color, src, image->depth);
+				color = mColorConvert(color, image->format, format);
+				PUT_PIXEL(color, dst, newImage->depth);
+			}
 		}
 	}
 	return newImage;
 }
 
 void mImageDestroy(struct mImage* image) {
+	if (image->palette) {
+		free(image->palette);
+	}
 	free(image->data);
 	free(image);
 }
@@ -280,7 +334,12 @@ uint32_t mImageGetPixelRaw(const struct mImage* image, unsigned x, unsigned y) {
 }
 
 uint32_t mImageGetPixel(const struct mImage* image, unsigned x, unsigned y) {
-	return mColorConvert(mImageGetPixelRaw(image, x, y), image->format, mCOLOR_ARGB8);
+	uint32_t raw = mImageGetPixelRaw(image, x, y);
+	if (image->format == mCOLOR_PAL8) {
+		return image->palette[raw];
+	} else {
+		return mColorConvert(raw, image->format, mCOLOR_ARGB8);
+	}
 }
 
 void mImageSetPixelRaw(struct mImage* image, unsigned x, unsigned y, uint32_t color) {
@@ -531,6 +590,7 @@ uint32_t mColorConvert(uint32_t color, enum mColorFormat from, enum mColorFormat
 		b = color;
 		break;
 
+	case mCOLOR_PAL8:
 	case mCOLOR_ANY:
 		return 0;
 	}
@@ -619,6 +679,7 @@ uint32_t mColorConvert(uint32_t color, enum mColorFormat from, enum mColorFormat
 		// sRGB primaries in fixed point, roughly fudged to saturate to 0xFFFF
 		color = (55 * r + 184 * g + 18 * b) >> 8;
 		break;
+	case mCOLOR_PAL8:
 	case mCOLOR_ANY:
 		return 0;
 	}

src/util/test/image.c

@@ -464,9 +464,8 @@ M_TEST_DEFINE(loadPng24) {
 		0x51, 0xc0, 0x4b, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae,
 		0x42, 0x60, 0x82
 	};
-	size_t len = 75;
 
-	struct VFile* vf = VFileFromConstMemory(data, len);
+	struct VFile* vf = VFileFromConstMemory(data, sizeof(data));
 	struct mImage* image = mImageLoadVF(vf);
 	vf->close(vf);
 
@@ -483,9 +482,8 @@ M_TEST_DEFINE(loadPng24) {
 	mImageDestroy(image);
 }
 
-
 M_TEST_DEFINE(loadPng32) {
-	unsigned char data[] = {
+	const uint8_t data[] = {
 		0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
 		0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x02,
 		0x08, 0x06, 0x00, 0x00, 0x00, 0x72, 0xb6, 0x0d, 0x24, 0x00, 0x00, 0x00,
@@ -494,9 +492,8 @@ M_TEST_DEFINE(loadPng32) {
 		0xa7, 0x5a, 0x78, 0x58, 0x7b, 0x07, 0xac, 0xe9, 0x00, 0x3d, 0x95, 0x00,
 		0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae, 0x42, 0x60, 0x82
 	};
-	unsigned int len = 83;
 
-	struct VFile* vf = VFileFromConstMemory(data, len);
+	struct VFile* vf = VFileFromConstMemory(data, sizeof(data));
 	struct mImage* image = mImageLoadVF(vf);
 	vf->close(vf);
 
@@ -513,6 +510,37 @@ M_TEST_DEFINE(loadPng32) {
 	mImageDestroy(image);
 }
 
+M_TEST_DEFINE(loadPngPalette) {
+	const uint8_t data[] = {
+		0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x00, 0x00, 0x00, 0x0d,
+		0x49, 0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x02,
+		0x08, 0x03, 0x00, 0x00, 0x00, 0x45, 0x68, 0xfd, 0x16, 0x00, 0x00, 0x00,
+		0x0c, 0x50, 0x4c, 0x54, 0x45, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00,
+		0xff, 0x00, 0x00, 0x00, 0xff, 0x9b, 0xc0, 0x13, 0xdc, 0x00, 0x00, 0x00,
+		0x04, 0x74, 0x52, 0x4e, 0x53, 0x00, 0xc0, 0x80, 0x40, 0x6f, 0x63, 0x29,
+		0x01, 0x00, 0x00, 0x00, 0x0e, 0x49, 0x44, 0x41, 0x54, 0x08, 0x99, 0x63,
+		0x60, 0x60, 0x64, 0x60, 0x62, 0x06, 0x00, 0x00, 0x11, 0x00, 0x07, 0x69,
+		0xe2, 0x2a, 0x44, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4e, 0x44, 0xae,
+		0x42, 0x60, 0x82
+	};
+
+	struct VFile* vf = VFileFromConstMemory(data, sizeof(data));
+	struct mImage* image = mImageLoadVF(vf);
+	vf->close(vf);
+
+	assert_non_null(image);
+	assert_int_equal(image->width, 2);
+	assert_int_equal(image->height, 2);
+	assert_int_equal(image->format, mCOLOR_PAL8);
+
+	assert_int_equal(mImageGetPixel(image, 0, 0), 0x00000000);
+	assert_int_equal(mImageGetPixel(image, 1, 0), 0xC0FF0000);
+	assert_int_equal(mImageGetPixel(image, 0, 1), 0x8000FF00);
+	assert_int_equal(mImageGetPixel(image, 1, 1), 0x400000FF);
+
+	mImageDestroy(image);
+}
+
 M_TEST_DEFINE(savePngNative) {
 	struct mImage* image = mImageCreate(1, 1, mCOLOR_ABGR8);
 	mImageSetPixel(image, 0, 0, 0x01234567);
@@ -1069,6 +1097,7 @@ M_TEST_SUITE_DEFINE(Image,
 #ifdef USE_PNG
 	cmocka_unit_test(loadPng24),
 	cmocka_unit_test(loadPng32),
+	cmocka_unit_test(loadPngPalette),
 	cmocka_unit_test(savePngNative),
 	cmocka_unit_test(savePngNonNative),
 	cmocka_unit_test(savePngRoundTrip),