Fix png encoding in skia debugger

tools/debugger/SkDrawCommand.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkDrawCommand.h"
 
 #include "SkBlurMaskFilter.h"
 #include "SkColorFilter.h"
 #include "SkDashPathEffect.h"
 #include "SkImageFilter.h"
 #include "SkJsonWriteBuffer.h"
 #include "SkMaskFilter.h"
 #include "SkObjectParser.h"
 #include "SkPaintDefaults.h"
 #include "SkPathEffect.h"
 #include "SkPicture.h"
 #include "SkTextBlob.h"
 #include "SkTextBlobRunIterator.h"
 #include "SkTHash.h"
 #include "SkTypeface.h"
 #include "SkValidatingReadBuffer.h"
 #include "SkWriteBuffer.h"
+#include "picture_utils.h"
 
 #define SKDEBUGCANVAS_ATTRIBUTE_COMMAND           "command"
 #define SKDEBUGCANVAS_ATTRIBUTE_VISIBLE           "visible"
 #define SKDEBUGCANVAS_ATTRIBUTE_MATRIX            "matrix"
 #define SKDEBUGCANVAS_ATTRIBUTE_COORDS            "coords"
 #define SKDEBUGCANVAS_ATTRIBUTE_BOUNDS            "bounds"
 #define SKDEBUGCANVAS_ATTRIBUTE_PAINT             "paint"
 #define SKDEBUGCANVAS_ATTRIBUTE_OUTER             "outer"
 #define SKDEBUGCANVAS_ATTRIBUTE_INNER             "inner"
 #define SKDEBUGCANVAS_ATTRIBUTE_MODE              "mode"
@@ skipping 573 matching lines @@
     (*target) = jsonFlattenable;
     sk_free(data);
 }
 
 static void write_png_callback(png_structp png_ptr, png_bytep data, png_size_t length) {
     SkWStream* out = (SkWStream*) png_get_io_ptr(png_ptr);
     out->write(data, length);
 }
 
 void SkDrawCommand::WritePNG(const png_bytep rgba, png_uint_32 width, png_uint_32 height,
-                             SkWStream& out) {
+                             SkWStream& out, bool isOpaque) {
     png_structp png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
     SkASSERT(png != nullptr);
     png_infop info_ptr = png_create_info_struct(png);
     SkASSERT(info_ptr != nullptr);
     if (setjmp(png_jmpbuf(png))) {
         SkFAIL("png encode error");
     }
-    png_set_IHDR(png, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+    png_set_write_fn(png, &out, write_png_callback, NULL);
+    int colorType = isOpaque ? PNG_COLOR_TYPE_RGB : PNG_COLOR_TYPE_RGBA;
+    png_set_IHDR(png, info_ptr, width, height, 8, colorType, PNG_INTERLACE_NONE,
                  PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
     png_set_compression_level(png, 1);
     png_bytepp rows = (png_bytepp) sk_malloc_throw(height * sizeof(png_byte*));
-    png_bytep pixels = (png_bytep) sk_malloc_throw(width * height * 3);
+    png_bytep pixels = (png_bytep) sk_malloc_throw(width * height * 4);
     for (png_size_t y = 0; y < height; ++y) {
         const png_bytep src = rgba + y * width * 4;
-        rows[y] = pixels + y * width * 3;
-        // convert from RGBA to RGB
+        rows[y] = pixels + y * width * 4;
         for (png_size_t x = 0; x < width; ++x) {
-            rows[y][x * 3] = src[x * 4];
-            rows[y][x * 3 + 1] = src[x * 4 + 1];
-            rows[y][x * 3 + 2] = src[x * 4 + 2];
+            rows[y][x * 4] = src[x * 4];
+            rows[y][x * 4 + 1] = src[x * 4 + 1];
+            rows[y][x * 4 + 2] = src[x * 4 + 2];
+            rows[y][x * 4 + 3] = src[x * 4 + 3];
         }
     }
+    png_write_info(png, info_ptr);
+    if (isOpaque) {
+        png_set_filler(png, 0xFF, PNG_FILLER_AFTER);
+    }
     png_set_filter(png, 0, PNG_NO_FILTERS);
-    png_set_rows(png, info_ptr, &rows[0]);
-    png_set_write_fn(png, &out, write_png_callback, NULL);
-    png_write_png(png, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
+    png_write_image(png, &rows[0]);
     png_destroy_write_struct(&png, NULL);
     sk_free(rows);
     sk_free(pixels);
 }
 
 bool SkDrawCommand::flatten(const SkImage& image, Json::Value* target,
                             UrlDataManager& urlDataManager) {
     size_t rowBytes = 4 * image.width();
     SkAutoFree buffer(sk_malloc_throw(rowBytes * image.height()));
     SkImageInfo dstInfo = SkImageInfo::Make(image.width(), image.height(),
                                             kN32_SkColorType, kPremul_SkAlphaType);
     if (!image.readPixels(dstInfo, buffer.get(), rowBytes, 0, 0)) {
         SkDebugf("readPixels failed\n");
         return false;
     }
+
+    SkBitmap bm;
+    bm.installPixels(dstInfo, buffer.get(), rowBytes);
+    sk_sp<SkData> encodedBitmap = sk_tools::encode_bitmap_for_png(bm);
+
     SkDynamicMemoryWStream out;
-    SkDrawCommand::WritePNG((png_bytep) buffer.get(), image.width(), image.height(), out);
+    SkDrawCommand::WritePNG((const png_bytep) encodedBitmap->bytes(), image.width(), image.height(),
+                            out, false);
     SkData* encoded = out.copyToData();
     Json::Value jsonData;
     encode_data(encoded->data(), encoded->size(), "image/png", urlDataManager, &jsonData);
     (*target)[SKDEBUGCANVAS_ATTRIBUTE_DATA] = jsonData;
     encoded->unref();
     return true;
 }
 
 static const char* color_type_name(SkColorType colorType) {
     switch (colorType) {
@@ skipping 2458 matching lines @@
     result[SKDEBUGCANVAS_ATTRIBUTE_MATRIX] = MakeJsonMatrix(fMatrix);
     return result;
 }
 
 SkSetMatrixCommand* SkSetMatrixCommand::fromJSON(Json::Value& command,
                                                  UrlDataManager& urlDataManager) {
     SkMatrix matrix;
     extract_json_matrix(command[SKDEBUGCANVAS_ATTRIBUTE_MATRIX], &matrix);
     return new SkSetMatrixCommand(matrix);
 }