Lossy compression of RGBA images (on WAN connection)

The RGB channels are compressed using JPEG.
The alpha channel is compressed using LZ.

3 files changed, 107 insertions, 6 deletions

diff --git a/common/canvas_base.c b/common/canvas_base.c
index 0148270f..2b00f09e 100644
--- a/common/canvas_base.c
+++ b/common/canvas_base.c
@@ -65,6 +65,10 @@
 
 #define ROUND(_x) ((int)floor((_x) + 0.5))
 
+#define IS_IMAGE_LOSSY(descriptor)                         \
+    (((descriptor)->type == SPICE_IMAGE_TYPE_JPEG) ||      \
+    ((descriptor)->type == SPICE_IMAGE_TYPE_JPEG_ALPHA))
+
 #ifdef WIN32
 typedef struct  __declspec (align(1)) LZImage {
 #else
@@ -607,6 +611,85 @@ static pixman_image_t *canvas_get_jpeg(CanvasBase *canvas, SpiceJPEGImage *image
     return surface;
 }
 
+static pixman_image_t *canvas_get_jpeg_alpha(CanvasBase *canvas,
+                                             SpiceJPEGAlphaImage *image, int invers)
+{
+    pixman_image_t *surface = NULL;
+    int stride;
+    int width;
+    int height;
+    uint8_t *dest;
+    int alpha_top_down = FALSE;
+    LzData *lz_data = &canvas->lz_data;
+    LzImageType lz_alpha_type;
+    uint8_t *comp_alpha_buf = NULL;
+    uint8_t *decomp_alpha_buf = NULL;
+    int alpha_size;
+    int lz_alpha_width, lz_alpha_height, n_comp_pixels, lz_alpha_top_down;
+
+    canvas->jpeg->ops->begin_decode(canvas->jpeg, image->jpeg_alpha.data,
+                                    image->jpeg_alpha.jpeg_size,
+                                    &width, &height);
+    ASSERT((uint32_t)width == image->descriptor.width);
+    ASSERT((uint32_t)height == image->descriptor.height);
+
+    if (image->jpeg_alpha.flags & SPICE_JPEG_ALPHA_FLAGS_TOP_DOWN) {
+        alpha_top_down = TRUE;
+    }
+
+#ifdef WIN32
+    lz_data->decode_data.dc = canvas->dc;
+#endif
+    surface = alloc_lz_image_surface(&lz_data->decode_data, PIXMAN_a8r8g8b8,
+                                     width, height, width*height, alpha_top_down);
+ 
+    if (surface == NULL) {
+        CANVAS_ERROR("create surface failed");
+    }
+
+    dest = (uint8_t *)pixman_image_get_data(surface);
+    stride = pixman_image_get_stride(surface);
+
+    canvas->jpeg->ops->decode(canvas->jpeg, dest, stride, SPICE_BITMAP_FMT_32BIT);
+    
+    comp_alpha_buf = image->jpeg_alpha.data + image->jpeg_alpha.jpeg_size;
+    alpha_size = image->jpeg_alpha.data_size - image->jpeg_alpha.jpeg_size;
+
+    lz_decode_begin(lz_data->lz, comp_alpha_buf, alpha_size, &lz_alpha_type,
+                    &lz_alpha_width, &lz_alpha_height, &n_comp_pixels,
+                    &lz_alpha_top_down, NULL);
+    ASSERT(lz_alpha_type == LZ_IMAGE_TYPE_XXXA);
+    ASSERT(lz_alpha_top_down == alpha_top_down);
+    ASSERT(lz_alpha_width == width);
+    ASSERT(lz_alpha_height == height);
+    ASSERT(n_comp_pixels == width * height);
+
+    if (!alpha_top_down) {
+        decomp_alpha_buf = dest + stride * (height - 1);
+    } else {
+        decomp_alpha_buf = dest;
+    }
+    lz_decode(lz_data->lz, LZ_IMAGE_TYPE_XXXA, decomp_alpha_buf);
+    
+    if (invers) {
+        uint8_t *end = dest + height * stride;
+        for (; dest != end; dest += stride) {
+            uint32_t *pix;
+            uint32_t *end_pix;
+
+            pix = (uint32_t *)dest;
+            end_pix = pix + width;
+            for (; pix < end_pix; pix++) {
+                *pix ^= 0x00ffffff;
+            }
+        }
+    }
+#ifdef DUMP_JPEG
+    dump_jpeg(image->jpeg_alpha.data, image->jpeg_alpha.jpeg_size);
+#endif
+    return surface;
+}
+
 static pixman_image_t *canvas_bitmap_to_surface(CanvasBase *canvas, SpiceBitmap* bitmap,
                                                 SpicePalette *palette, int want_original)
 {
@@ -1088,6 +1171,11 @@ static pixman_image_t *canvas_get_image_internal(CanvasBase *canvas, SPICE_ADDRE
         surface = canvas_get_jpeg(canvas, image, 0);
         break;
     }
+    case SPICE_IMAGE_TYPE_JPEG_ALPHA: {
+        SpiceJPEGAlphaImage *image = (SpiceJPEGAlphaImage *)descriptor;
+        surface = canvas_get_jpeg_alpha(canvas, image, 0);
+        break;
+    }
 #if defined(SW_CANVAS_CACHE)
     case SPICE_IMAGE_TYPE_GLZ_RGB: {
         LZImage *image = (LZImage *)descriptor;
@@ -1138,7 +1226,7 @@ static pixman_image_t *canvas_get_image_internal(CanvasBase *canvas, SPICE_ADDRE
 #endif
         descriptor->type != SPICE_IMAGE_TYPE_FROM_CACHE ) {
 #ifdef SW_CANVAS_CACHE
-       if (descriptor->type != SPICE_IMAGE_TYPE_JPEG) {
+        if (!IS_IMAGE_LOSSY(descriptor)) {
             canvas->bits_cache->ops->put(canvas->bits_cache, descriptor->id, surface);
         } else {
             canvas->bits_cache->ops->put_lossy(canvas->bits_cache, descriptor->id, surface);
@@ -1151,7 +1239,7 @@ static pixman_image_t *canvas_get_image_internal(CanvasBase *canvas, SPICE_ADDRE
 #endif
 #ifdef SW_CANVAS_CACHE
     } else if (descriptor->flags & SPICE_IMAGE_FLAGS_CACHE_REPLACE_ME) {
-        if (descriptor->type == SPICE_IMAGE_TYPE_JPEG) {
+        if (IS_IMAGE_LOSSY(descriptor)) {
             CANVAS_ERROR("invalid cache replace request: the image is lossy");
         }
         canvas->bits_cache->ops->replace_lossy(canvas->bits_cache, descriptor->id, surface);
diff --git a/common/lz.c b/common/lz.c
index 73a797c7..e5635849 100644
--- a/common/lz.c
+++ b/common/lz.c
@@ -565,6 +565,9 @@ int lz_encode(LzContext *lz, LzImageType type, int width, int height, int top_do
         lz_rgb32_compress(encoder);
         lz_rgb_alpha_compress(encoder);
         break;
+    case LZ_IMAGE_TYPE_XXXA:
+        lz_rgb_alpha_compress(encoder);
+        break;
     case LZ_IMAGE_TYPE_INVALID:
     default:
         encoder->usr->error(encoder->usr, "bad image type\n");
@@ -661,6 +664,7 @@ void lz_decode(LzContext *lz, LzImageType to_type, uint8_t *buf)
             case LZ_IMAGE_TYPE_RGB24:
             case LZ_IMAGE_TYPE_RGB32:
             case LZ_IMAGE_TYPE_RGBA:
+            case LZ_IMAGE_TYPE_XXXA:
             case LZ_IMAGE_TYPE_INVALID:
             default:
                 encoder->usr->error(encoder->usr, "bad image type\n");
@@ -705,6 +709,14 @@ void lz_decode(LzContext *lz, LzImageType to_type, uint8_t *buf)
                 encoder->usr->error(encoder->usr, "unsupported output format\n");
             }
             break;
+        case LZ_IMAGE_TYPE_XXXA:
+            if (encoder->type == to_type) {
+                alpha_size = lz_rgb_alpha_decompress(encoder, (rgb32_pixel_t *)buf, size);
+                out_size = alpha_size;
+            } else {
+                encoder->usr->error(encoder->usr, "unsupported output format\n");
+            }
+            break;
         case LZ_IMAGE_TYPE_PLT1_LE:
         case LZ_IMAGE_TYPE_PLT1_BE:
         case LZ_IMAGE_TYPE_PLT4_LE:
diff --git a/common/lz_common.h b/common/lz_common.h
index d5019fd3..34276afb 100644
--- a/common/lz_common.h
+++ b/common/lz_common.h
@@ -39,17 +39,18 @@ typedef enum {
     LZ_IMAGE_TYPE_RGB16,
     LZ_IMAGE_TYPE_RGB24,
     LZ_IMAGE_TYPE_RGB32,
-    LZ_IMAGE_TYPE_RGBA
+    LZ_IMAGE_TYPE_RGBA,
+    LZ_IMAGE_TYPE_XXXA
 } LzImageType;
 
 #define LZ_IMAGE_TYPE_MASK 0x0f
 #define LZ_IMAGE_TYPE_LOG 4 // number of bits required for coding the image type
 
 /* access to the arrays is based on the image types */
-static const int IS_IMAGE_TYPE_PLT[] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0};
-static const int IS_IMAGE_TYPE_RGB[] = {0, 0, 0, 0, 0, 0, 1, 1, 1, 1};
+static const int IS_IMAGE_TYPE_PLT[] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0};
+static const int IS_IMAGE_TYPE_RGB[] = {0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1};
 static const int PLT_PIXELS_PER_BYTE[] = {0, 8, 8, 2, 2, 1};
-static const int RGB_BYTES_PER_PIXEL[] = {0, 1, 1, 1, 1, 1, 2, 3, 4, 4};
+static const int RGB_BYTES_PER_PIXEL[] = {0, 1, 1, 1, 1, 1, 2, 3, 4, 4, 4};
 
 
 #define LZ_MAGIC (*(uint32_t *)"LZ  ")