refactor image resource loading code in minui
Reduce the number of copies of libpng boilerplate. Rename
res_create_* functions to be more clear. Make explicit the use of the
framebuffer pixel format for images, and handle more combinations of
input and output (eg, loading a grayscale image for display rather
than use as a text alpha channel).
Change-Id: I3d41c800a8f4c22b2f0167967ce6ee4d6b2b8846
diff --git a/minui/resources.c b/minui/resources.c
index a6528b3..69fd14b 100644
--- a/minui/resources.c
+++ b/minui/resources.c
@@ -44,15 +44,11 @@
return surface;
}
-int res_create_surface(const char* name, gr_surface* pSurface) {
+static int open_png(const char* name, png_structp* png_ptr, png_infop* info_ptr,
+ png_uint_32* width, png_uint_32* height, png_byte* channels) {
char resPath[256];
- gr_surface surface = NULL;
- int result = 0;
unsigned char header[8];
- png_structp png_ptr = NULL;
- png_infop info_ptr = NULL;
-
- *pSurface = NULL;
+ int result = 0;
snprintf(resPath, sizeof(resPath)-1, "/res/images/%s.png", name);
resPath[sizeof(resPath)-1] = '\0';
@@ -73,170 +69,182 @@
goto exit;
}
- png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
- if (!png_ptr) {
+ *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+ if (!*png_ptr) {
result = -4;
goto exit;
}
- info_ptr = png_create_info_struct(png_ptr);
- if (!info_ptr) {
+ *info_ptr = png_create_info_struct(*png_ptr);
+ if (!*info_ptr) {
result = -5;
goto exit;
}
- if (setjmp(png_jmpbuf(png_ptr))) {
+ if (setjmp(png_jmpbuf(*png_ptr))) {
result = -6;
goto exit;
}
- png_init_io(png_ptr, fp);
- png_set_sig_bytes(png_ptr, sizeof(header));
- png_read_info(png_ptr, info_ptr);
+ png_init_io(*png_ptr, fp);
+ png_set_sig_bytes(*png_ptr, sizeof(header));
+ png_read_info(*png_ptr, *info_ptr);
int color_type, bit_depth;
- png_uint_32 width, height;
- png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth,
+ png_get_IHDR(*png_ptr, *info_ptr, width, height, &bit_depth,
&color_type, NULL, NULL, NULL);
- int channels = png_get_channels(png_ptr, info_ptr);
+ *channels = png_get_channels(*png_ptr, *info_ptr);
- if (!(bit_depth <= 8 &&
- ((channels == 3 && color_type == PNG_COLOR_TYPE_RGB) ||
- (channels == 1 && (color_type == PNG_COLOR_TYPE_PALETTE ||
- color_type == PNG_COLOR_TYPE_GRAY))))) {
- return -7;
+ if (bit_depth == 8 && *channels == 3 && color_type == PNG_COLOR_TYPE_RGB) {
+ // 8-bit RGB images: great, nothing to do.
+ } else if (bit_depth <= 8 && *channels == 1 && color_type == PNG_COLOR_TYPE_GRAY) {
+ // 1-, 2-, 4-, or 8-bit gray images: expand to 8-bit gray.
+ png_set_expand_gray_1_2_4_to_8(*png_ptr);
+ } else if (bit_depth == 8 && *channels == 1 && color_type == PNG_COLOR_TYPE_PALETTE) {
+ // paletted images: expand to 8-bit RGB. Note that we DON'T
+ // currently expand the tRNS chunk (if any) to an alpha
+ // channel, because minui doesn't support alpha channels in
+ // general.
+ png_set_palette_to_rgb(*png_ptr);
+ *channels = 3;
+ } else {
+ fprintf(stderr, "minui doesn't support PNG depth %d channels %d color_type %d\n",
+ bit_depth, (int) channels, color_type);
+ result = -7;
goto exit;
}
- size_t stride = (color_type == PNG_COLOR_TYPE_GRAY ? 1 : 4) * width;
+ return result;
- surface = malloc_surface(stride * height);
+ exit:
+ if (result < 0) {
+ png_destroy_read_struct(png_ptr, info_ptr, NULL);
+ }
+ if (fp != NULL) {
+ fclose(fp);
+ }
+
+ return result;
+}
+
+// "display" surfaces are transformed into the framebuffer's required
+// pixel format (currently only RGBX is supported) at load time, so
+// gr_blit() can be nothing more than a memcpy() for each row. The
+// next two functions are the only ones that know anything about the
+// framebuffer pixel format; they need to be modified if the
+// framebuffer format changes (but nothing else should).
+
+// Allocate and return a gr_surface sufficient for storing an image of
+// the indicated size in the framebuffer pixel format.
+static gr_surface init_display_surface(png_uint_32 width, png_uint_32 height) {
+ gr_surface surface;
+
+ surface = malloc_surface(width * height * 4);
+ if (surface == NULL) return NULL;
+
+ surface->width = width;
+ surface->height = height;
+ surface->row_bytes = width * 4;
+ surface->pixel_bytes = 4;
+
+ return surface;
+}
+
+// Copy 'input_row' to 'output_row', transforming it to the
+// framebuffer pixel format. The input format depends on the value of
+// 'channels':
+//
+// 1 - input is 8-bit grayscale
+// 3 - input is 24-bit RGB
+// 4 - input is 32-bit RGBA/RGBX
+//
+// 'width' is the number of pixels in the row.
+static void transform_rgb_to_draw(unsigned char* input_row,
+ unsigned char* output_row,
+ int channels, int width) {
+ int x;
+ unsigned char* ip = input_row;
+ unsigned char* op = output_row;
+
+ switch (channels) {
+ case 1:
+ // expand gray level to RGBX
+ for (x = 0; x < width; ++x) {
+ *op++ = *ip;
+ *op++ = *ip;
+ *op++ = *ip;
+ *op++ = 0xff;
+ ip++;
+ }
+ break;
+
+ case 3:
+ // expand RGBA to RGBX
+ for (x = 0; x < width; ++x) {
+ *op++ = *ip++;
+ *op++ = *ip++;
+ *op++ = *ip++;
+ *op++ = 0xff;
+ }
+ break;
+
+ case 4:
+ // copy RGBA to RGBX
+ memcpy(output_row, input_row, width*4);
+ break;
+ }
+}
+
+int res_create_display_surface(const char* name, gr_surface* pSurface) {
+ gr_surface surface = NULL;
+ int result = 0;
+ png_structp png_ptr = NULL;
+ png_infop info_ptr = NULL;
+ png_uint_32 width, height;
+ png_byte channels;
+
+ *pSurface = NULL;
+
+ result = open_png(name, &png_ptr, &info_ptr, &width, &height, &channels);
+ if (result < 0) return result;
+
+ surface = init_display_surface(width, height);
if (surface == NULL) {
result = -8;
goto exit;
}
- unsigned char* pData = surface->data;
- surface->width = width;
- surface->height = height;
- surface->row_bytes = stride;
- surface->pixel_bytes = (color_type == PNG_COLOR_TYPE_GRAY ? 1 : 4);
- int alpha = (channels == 4);
- png_set_expand(png_ptr);
- if (color_type == PNG_COLOR_TYPE_GRAY) {
- alpha = 1;
- }
-
+ unsigned char* p_row = malloc(width * 4);
unsigned int y;
- if (channels == 3 || (channels == 1 && !alpha)) {
- for (y = 0; y < height; ++y) {
- unsigned char* pRow = pData + y * stride;
- png_read_row(png_ptr, pRow, NULL);
-
- int x;
- for(x = width - 1; x >= 0; x--) {
- int sx = x * 3;
- int dx = x * 4;
- unsigned char r = pRow[sx];
- unsigned char g = pRow[sx + 1];
- unsigned char b = pRow[sx + 2];
- unsigned char a = 0xff;
- pRow[dx ] = r; // r
- pRow[dx + 1] = g; // g
- pRow[dx + 2] = b; // b
- pRow[dx + 3] = a;
- }
- }
- } else {
- for (y = 0; y < height; ++y) {
- unsigned char* pRow = pData + y * stride;
- png_read_row(png_ptr, pRow, NULL);
- }
+ for (y = 0; y < height; ++y) {
+ png_read_row(png_ptr, p_row, NULL);
+ transform_rgb_to_draw(p_row, surface->data + y * surface->row_bytes, channels, width);
}
+ free(p_row);
- *pSurface = (gr_surface) surface;
+ *pSurface = surface;
-exit:
+ exit:
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
- if (fp != NULL) {
- fclose(fp);
- }
- if (result < 0) {
- if (surface) {
- free(surface);
- }
- }
+ if (result < 0 && surface != NULL) free(surface);
return result;
}
-int res_create_multi_surface(const char* name, int* frames, gr_surface** pSurface) {
- char resPath[256];
+int res_create_multi_display_surface(const char* name, int* frames, gr_surface** pSurface) {
+ gr_surface* surface = NULL;
int result = 0;
- unsigned char header[8];
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
+ png_uint_32 width, height;
+ png_byte channels;
int i;
- gr_surface* surface = NULL;
*pSurface = NULL;
*frames = -1;
- snprintf(resPath, sizeof(resPath)-1, "/res/images/%s.png", name);
- resPath[sizeof(resPath)-1] = '\0';
- FILE* fp = fopen(resPath, "rb");
- if (fp == NULL) {
- result = -1;
- goto exit;
- }
-
- size_t bytesRead = fread(header, 1, sizeof(header), fp);
- if (bytesRead != sizeof(header)) {
- result = -2;
- goto exit;
- }
-
- if (png_sig_cmp(header, 0, sizeof(header))) {
- result = -3;
- goto exit;
- }
-
- png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
- if (!png_ptr) {
- result = -4;
- goto exit;
- }
-
- info_ptr = png_create_info_struct(png_ptr);
- if (!info_ptr) {
- result = -5;
- goto exit;
- }
-
- if (setjmp(png_jmpbuf(png_ptr))) {
- result = -6;
- goto exit;
- }
-
- png_init_io(png_ptr, fp);
- png_set_sig_bytes(png_ptr, sizeof(header));
- png_read_info(png_ptr, info_ptr);
-
- int color_type, bit_depth;
- png_uint_32 width, height;
- png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth,
- &color_type, NULL, NULL, NULL);
-
- int channels = png_get_channels(png_ptr, info_ptr);
-
- if (!(bit_depth <= 8 &&
- ((channels == 3 && color_type == PNG_COLOR_TYPE_RGB) ||
- (channels == 1 && (color_type == PNG_COLOR_TYPE_PALETTE ||
- color_type == PNG_COLOR_TYPE_GRAY))))) {
- return -7;
- goto exit;
- }
+ result = open_png(name, &png_ptr, &info_ptr, &width, &height, &channels);
+ if (result < 0) return result;
*frames = 1;
png_textp text;
@@ -257,67 +265,35 @@
goto exit;
}
- size_t stride = (color_type == PNG_COLOR_TYPE_GRAY ? 1 : 4) * width;
- size_t pixelSize = stride * height / *frames;
-
surface = malloc(*frames * sizeof(gr_surface));
if (surface == NULL) {
result = -8;
goto exit;
}
for (i = 0; i < *frames; ++i) {
- surface[i] = malloc_surface(pixelSize);
- surface[i]->width = width;
- surface[i]->height = height / *frames;
- surface[i]->row_bytes = stride;
- surface[i]->pixel_bytes = (color_type == PNG_COLOR_TYPE_GRAY ? 1 : 4);
- }
-
- int alpha = (channels == 4);
- png_set_expand(png_ptr);
- if (color_type == PNG_COLOR_TYPE_GRAY) {
- alpha = 1;
- }
-
- png_uint_32 y;
- if (channels == 3 || (channels == 1 && !alpha)) {
- for (y = 0; y < height; ++y) {
- int fy = y / *frames;
- int fr = y % *frames;
- unsigned char* pRow = surface[fr]->data + fy * stride;
- png_read_row(png_ptr, pRow, NULL);
-
- int x;
- for(x = width - 1; x >= 0; x--) {
- int sx = x * 3;
- int dx = x * 4;
- unsigned char r = pRow[sx];
- unsigned char g = pRow[sx + 1];
- unsigned char b = pRow[sx + 2];
- unsigned char a = 0xff;
- pRow[dx ] = r; // r
- pRow[dx + 1] = g; // g
- pRow[dx + 2] = b; // b
- pRow[dx + 3] = a;
- }
- }
- } else {
- for (y = 0; y < height; ++y) {
- int fy = y / *frames;
- int fr = y % *frames;
- unsigned char* pRow = surface[fr]->data + fy * stride;
- png_read_row(png_ptr, pRow, NULL);
+ surface[i] = init_display_surface(width, height / *frames);
+ if (surface[i] == NULL) {
+ result = -8;
+ goto exit;
}
}
+ unsigned char* p_row = malloc(width * 4);
+ unsigned int y;
+ for (y = 0; y < height; ++y) {
+ png_read_row(png_ptr, p_row, NULL);
+ int frame = y % *frames;
+ unsigned char* out_row = surface[frame]->data +
+ (y / *frames) * surface[frame]->row_bytes;
+ transform_rgb_to_draw(p_row, out_row, channels, width);
+ }
+ free(p_row);
+
*pSurface = (gr_surface*) surface;
exit:
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
- if (fp != NULL) {
- fclose(fp);
- }
if (result < 0) {
if (surface) {
for (i = 0; i < *frames; ++i) {
@@ -329,7 +305,50 @@
return result;
}
-static int matches_locale(const char* loc) {
+int res_create_alpha_surface(const char* name, gr_surface* pSurface) {
+ gr_surface surface = NULL;
+ int result = 0;
+ png_structp png_ptr = NULL;
+ png_infop info_ptr = NULL;
+ png_uint_32 width, height;
+ png_byte channels;
+
+ *pSurface = NULL;
+
+ result = open_png(name, &png_ptr, &info_ptr, &width, &height, &channels);
+ if (result < 0) return result;
+
+ if (channels != 1) {
+ result = -7;
+ goto exit;
+ }
+
+ surface = malloc_surface(width * height);
+ if (surface == NULL) {
+ result = -8;
+ goto exit;
+ }
+ surface->width = width;
+ surface->height = height;
+ surface->row_bytes = width;
+ surface->pixel_bytes = 1;
+
+ unsigned char* p_row;
+ unsigned int y;
+ for (y = 0; y < height; ++y) {
+ p_row = surface->data + y * surface->row_bytes;
+ png_read_row(png_ptr, p_row, NULL);
+ }
+
+ *pSurface = surface;
+
+ exit:
+ png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+ if (result < 0 && surface != NULL) free(surface);
+ return result;
+}
+
+static int matches_locale(const char* loc, const char* locale) {
if (locale == NULL) return 0;
if (strcmp(loc, locale) == 0) return 1;
@@ -346,70 +365,35 @@
return (strncmp(locale, loc, i) == 0 && locale[i] == '_');
}
-int res_create_localized_surface(const char* name, gr_surface* pSurface) {
- char resPath[256];
+int res_create_localized_alpha_surface(const char* name,
+ const char* locale,
+ gr_surface* pSurface) {
gr_surface surface = NULL;
int result = 0;
- unsigned char header[8];
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
+ png_uint_32 width, height;
+ png_byte channels;
*pSurface = NULL;
- snprintf(resPath, sizeof(resPath)-1, "/res/images/%s.png", name);
- resPath[sizeof(resPath)-1] = '\0';
- FILE* fp = fopen(resPath, "rb");
- if (fp == NULL) {
- result = -1;
+ if (locale == NULL) {
+ surface = malloc_surface(0);
+ surface->width = 0;
+ surface->height = 0;
+ surface->row_bytes = 0;
+ surface->pixel_bytes = 1;
goto exit;
}
- size_t bytesRead = fread(header, 1, sizeof(header), fp);
- if (bytesRead != sizeof(header)) {
- result = -2;
+ result = open_png(name, &png_ptr, &info_ptr, &width, &height, &channels);
+ if (result < 0) return result;
+
+ if (channels != 1) {
+ result = -7;
goto exit;
}
- if (png_sig_cmp(header, 0, sizeof(header))) {
- result = -3;
- goto exit;
- }
-
- png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
- if (!png_ptr) {
- result = -4;
- goto exit;
- }
-
- info_ptr = png_create_info_struct(png_ptr);
- if (!info_ptr) {
- result = -5;
- goto exit;
- }
-
- if (setjmp(png_jmpbuf(png_ptr))) {
- result = -6;
- goto exit;
- }
-
- png_init_io(png_ptr, fp);
- png_set_sig_bytes(png_ptr, sizeof(header));
- png_read_info(png_ptr, info_ptr);
-
- int color_type, bit_depth;
- png_uint_32 width, height;
- png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth,
- &color_type, NULL, NULL, NULL);
- int channels = png_get_channels(png_ptr, info_ptr);
-
- if (!(bit_depth <= 8 &&
- (channels == 1 && color_type == PNG_COLOR_TYPE_GRAY))) {
- return -7;
- goto exit;
- }
-
- png_set_expand(png_ptr);
-
unsigned char* row = malloc(width);
png_uint_32 y;
for (y = 0; y < height; ++y) {
@@ -419,7 +403,7 @@
int len = row[4];
char* loc = (char*)row+5;
- if (y+1+h >= height || matches_locale(loc)) {
+ if (y+1+h >= height || matches_locale(loc, locale)) {
printf(" %20s: %s (%d x %d @ %d)\n", name, loc, w, h, y);
surface = malloc_surface(w*h);
@@ -427,8 +411,6 @@
result = -8;
goto exit;
}
- unsigned char* pData = surface->data;
-
surface->width = w;
surface->height = h;
surface->row_bytes = w;
@@ -437,7 +419,7 @@
int i;
for (i = 0; i < h; ++i, ++y) {
png_read_row(png_ptr, row, NULL);
- memcpy(pData + i*w, row, w);
+ memcpy(surface->data + i*w, row, w);
}
*pSurface = (gr_surface) surface;
@@ -452,15 +434,7 @@
exit:
png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
- if (fp != NULL) {
- fclose(fp);
- }
- if (result < 0) {
- if (surface) {
- free(surface);
- }
- }
+ if (result < 0 && surface != NULL) free(surface);
return result;
}