1 files changed, 155 insertions, 83 deletions

diff --git a/minuitwrp/resources.c b/minuitwrp/resources.c
index 4dd10a9de..6f6d13b2b 100644
--- a/minuitwrp/resources.c
+++ b/minuitwrp/resources.c
@@ -42,25 +42,29 @@ double pow(double x, double y) {
     return x;
 }
 
-int res_create_surface_png(const char* name, gr_surface* pSurface) {
-    GGLSurface* surface = NULL;
-    int result = 0;
+#define SURFACE_DATA_ALIGNMENT 8
+
+static GGLSurface* malloc_surface(size_t data_size) {
+    unsigned char* temp = malloc(sizeof(GGLSurface) + data_size + SURFACE_DATA_ALIGNMENT);
+    if (temp == NULL) return NULL;
+    GGLSurface* surface = (GGLSurface*) temp;
+    surface->data = temp + sizeof(GGLSurface) +
+        (SURFACE_DATA_ALIGNMENT - (sizeof(GGLSurface) % SURFACE_DATA_ALIGNMENT));
+    return surface;
+}
+
+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];
     unsigned char header[8];
-    png_structp png_ptr = NULL;
-    png_infop info_ptr = NULL;
+    int result = 0;
 
-    FILE* fp = fopen(name, "rb");
+    snprintf(resPath, sizeof(resPath)-1, "/res/images/%s.png", name);
+    resPath[sizeof(resPath)-1] = '\0';
+    FILE* fp = fopen(resPath, "rb");
     if (fp == NULL) {
-        char resPath[256];
-
-        snprintf(resPath, sizeof(resPath)-1, "/res/images/%s.png", name);
-        resPath[sizeof(resPath)-1] = '\0';
-        fp = fopen(resPath, "rb");
-        if (fp == NULL)
-        {
-            result = -1;
-            goto exit;
-        }
+        result = -1;
+        goto exit;
     }
 
     size_t bytesRead = fread(header, 1, sizeof(header), fp);
@@ -74,105 +78,173 @@ int res_create_surface_png(const char* name, gr_surface* pSurface) {
         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_set_packing(png_ptr);
-
-    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;
-    size_t 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);
 
-    png_byte channels = png_get_channels(png_ptr, info_ptr);
-    size_t stride = 4 * width;
-    size_t pixelSize = stride * height;
-
-    if (!(bit_depth == 8 &&
-          ((channels == 3 && color_type == PNG_COLOR_TYPE_RGB) ||
-           (channels == 4 && color_type == PNG_COLOR_TYPE_RGBA) ||
-           (channels == 1 && color_type == PNG_COLOR_TYPE_PALETTE)))) {
-        return -7;
+    *channels = png_get_channels(*png_ptr, *info_ptr);
+
+    /*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, *channels, color_type);
+        result = -7;
         goto exit;
+    }*/
+    if (color_type == PNG_COLOR_TYPE_PALETTE) {
+        png_set_palette_to_rgb(png_ptr);
     }
 
-    surface = malloc(sizeof(GGLSurface) + pixelSize);
-    if (surface == NULL) {
-        result = -8;
-        goto exit;
+    return result;
+
+  exit:
+    if (result < 0) {
+        png_destroy_read_struct(png_ptr, info_ptr, NULL);
     }
-    unsigned char* pData = (unsigned char*) (surface + 1);
+    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 GGLSurface* init_display_surface(png_uint_32 width, png_uint_32 height) {
+    GGLSurface* surface;
+
+    surface = (GGLSurface*) malloc_surface(width * height * 4);
+    if (surface == NULL) return NULL;
+
     surface->version = sizeof(GGLSurface);
     surface->width = width;
     surface->height = height;
-    surface->stride = width; /* Yes, pixels, not bytes */
-    surface->data = pData;
-    surface->format = (channels == 3) ?
-            GGL_PIXEL_FORMAT_RGBX_8888 : GGL_PIXEL_FORMAT_RGBA_8888;
+    surface->stride = width;
 
-    if (color_type == PNG_COLOR_TYPE_PALETTE) {
-        png_set_palette_to_rgb(png_ptr);
-    }
+    return surface;
+}
 
-    int y;
-    if (channels < 4) {
-        for (y = 0; y < (int) 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;
+// 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++;
             }
-        }
-    } else {
-        for (y = 0; y < (int) height; ++y) {
-            unsigned char* pRow = pData + y * stride;
-            png_read_row(png_ptr, pRow, NULL);
-        }
+            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;
     }
+}
 
-    *pSurface = (gr_surface) surface;
+int res_create_surface_png(const char* name, gr_surface* pSurface) {
+    GGLSurface* surface = NULL;
+    int result = 0;
+    png_structp png_ptr = NULL;
+    png_infop info_ptr = NULL;
+    png_uint_32 width, height;
+    png_byte channels;
 
-exit:
-    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+    *pSurface = NULL;
 
-    if (fp != NULL) {
-        fclose(fp);
+    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;
     }
-    if (result < 0) {
-        if (surface) {
-            free(surface);
-        }
+
+    unsigned char* p_row = malloc(width * 4);
+    unsigned int y;
+    for (y = 0; y < height; ++y) {
+        png_read_row(png_ptr, p_row, NULL);
+        transform_rgb_to_draw(p_row, surface->data + y * width * 4, channels, width);
     }
+    free(p_row);
+
+    if (channels == 3)
+        surface->format = GGL_PIXEL_FORMAT_RGBX_8888;
+    else
+        surface->format = GGL_PIXEL_FORMAT_RGBA_8888;
+
+    *pSurface = (gr_surface) surface;
+
+  exit:
+    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+    if (result < 0 && surface != NULL) free(surface);
     return result;
 }