Changeset 94591 in webkit

Timestamp:

Sep 6, 2011 12:50:19 PM (13 years ago)

Author:

noel.gordon@gmail.com

Message:

[chromium skia] JPEGImageEncoder: hoist constants out of the encoding loop
​https://bugs.webkit.org/show_bug.cgi?id=67589

Reviewed by Kenneth Russell.

Change the row converter function signatures to be the same. Call them via a function
pointer during the encoding loop. Minor webkit style cleanup, remove unused include.

No new tests. Covered by existing canvas 2d and 3d tests.
canvas/philip/tests/toDataURL.jpeg.alpha.html
fast/canvas/webgl/premultiplyalpha-test.html

• platform/image-encoders/skia/JPEGImageEncoder.cpp: Remove SkUnPreMultiply.h (not used).

(WebCore::preMultipliedBGRAtoRGB): Use unsigned char* instead of void* for pixels.
(WebCore::RGBAtoRGB): pixels & pixelCount to match the preMultipliedBGRAtoRGB() signature.
(WebCore::encodePixels): Move constants out of the encoding loop: use a function pointer
to call preMultipliedBGRAtoRGB or RGBAtoRGB (now they have identical signatures), define
and use pixelRowStride constant.
(WebCore::JPEGImageEncoder::encode):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/image-encoders/skia/JPEGImageEncoder.cpp (modified) (6 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2011-09-06  Noel Gordon  <noel.gordon@gmail.com>
+
+        [chromium skia] JPEGImageEncoder: hoist constants out of the encoding loop
+        https://bugs.webkit.org/show_bug.cgi?id=67589
+
+        Reviewed by Kenneth Russell.
+
+        Change the row converter function signatures to be the same.  Call them via a function
+        pointer during the encoding loop.  Minor webkit style cleanup, remove unused include.
+
+        No new tests.  Covered by existing canvas 2d and 3d tests.
+        canvas/philip/tests/toDataURL.jpeg.alpha.html
+        fast/canvas/webgl/premultiplyalpha-test.html
+
+        * platform/image-encoders/skia/JPEGImageEncoder.cpp:  Remove SkUnPreMultiply.h (not used).
+        (WebCore::preMultipliedBGRAtoRGB):  Use unsigned char* instead of void* for pixels.
+        (WebCore::RGBAtoRGB):  pixels & pixelCount to match the preMultipliedBGRAtoRGB() signature.
+        (WebCore::encodePixels):  Move constants out of the encoding loop: use a function pointer
+        to call preMultipliedBGRAtoRGB or RGBAtoRGB (now they have identical signatures), define
+        and use pixelRowStride constant.
+        (WebCore::JPEGImageEncoder::encode):
+
 2011-09-06  Aaron Colwell  <acolwell@chromium.org>
 

trunk/Source/WebCore/platform/image-encoders/skia/JPEGImageEncoder.cpp

@@ -36 +36 @@
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
-#include "SkUnPreMultiply.h"
 extern "C" {
 #include <stdio.h> // jpeglib.h needs stdio.h FILE
@@ -81 +80 @@
 }
 
-static void preMultipliedBGRAtoRGB(const void* pixels, unsigned int pixelCount, unsigned char* output)
+static void preMultipliedBGRAtoRGB(const unsigned char* pixels, unsigned int pixelCount, unsigned char* output)
 {
-    const SkPMColor* input = static_cast<const SkPMColor*>(pixels);
+    const SkPMColor* input = reinterpret_cast<const SkPMColor*>(pixels);
     for (; pixelCount-- > 0; ++input) {
         *output++ = SkGetPackedR32(*input);
@@ -91 +90 @@
 }
 
-static void RGBAtoRGB(const unsigned char* input, unsigned int pixels, unsigned char* output)
+static void RGBAtoRGB(const unsigned char* pixels, unsigned int pixelCount, unsigned char* output)
 {
-    for (; pixels-- > 0; input += 4) {
-        *output++ = input[0];
-        *output++ = input[1];
-        *output++ = input[2];
+    for (; pixelCount-- > 0; pixels += 4) {
+        *output++ = pixels[0];
+        *output++ = pixels[1];
+        *output++ = pixels[2];
     }
 }
 
-static bool encodePixels(const IntSize& inputSize, unsigned char* inputPixels,
-                         bool premultiplied, int quality, Vector<unsigned char>* output)
+static bool encodePixels(IntSize imageSize, unsigned char* inputPixels, bool premultiplied, int quality, Vector<unsigned char>* output)
 {
-    IntSize imageSize(inputSize);
-    imageSize.clampNegativeToZero();
     JPEGOutputBuffer destination;
     destination.output = output;
@@ -126 +122 @@
     cinfo.dest->empty_output_buffer = writeOutput;
     cinfo.dest->term_destination = finishOutput;
+
+    imageSize.clampNegativeToZero();
     cinfo.image_height = imageSize.height();
     cinfo.image_width = imageSize.width();
     cinfo.in_color_space = JCS_RGB;
     cinfo.input_components = 3;
+
+    void (*extractRowRGB)(const unsigned char*, unsigned int, unsigned char* output);
+    extractRowRGB = &RGBAtoRGB;
+    if (premultiplied)
+        extractRowRGB = &preMultipliedBGRAtoRGB;
 
     jpeg_set_defaults(&cinfo);
@@ -137 +140 @@
     unsigned char* pixels = inputPixels;
     row.resize(cinfo.image_width * cinfo.input_components);
+    const size_t pixelRowStride = cinfo.image_width * 4;
     while (cinfo.next_scanline < cinfo.image_height) {
-        if (premultiplied)
-            preMultipliedBGRAtoRGB(pixels, cinfo.image_width, row.data());
-        else 
-            RGBAtoRGB(pixels, cinfo.image_width, row.data());
+        extractRowRGB(pixels, cinfo.image_width, row.data());
         jpeg_write_scanlines(&cinfo, row.dataSlot(), 1);
-        pixels += cinfo.image_width * 4;
+        pixels += pixelRowStride;
     }
 
@@ -153 +154 @@
 bool JPEGImageEncoder::encode(const SkBitmap& bitmap, int quality, Vector<unsigned char>* output)
 {
+    SkAutoLockPixels bitmapLock(bitmap);
+
     if (bitmap.config() != SkBitmap::kARGB_8888_Config)
-        return false; // Only support ARGB 32 bpp skia bitmaps.
+        return false; // Only support 32 bit/pixel skia bitmaps.
 
-    SkAutoLockPixels bitmapLock(bitmap);
-    IntSize imageSize(bitmap.width(), bitmap.height());
-
-    return encodePixels(imageSize, static_cast<unsigned char *>(bitmap.getPixels()),
-                        true, quality, output);
+    return encodePixels(IntSize(bitmap.width(), bitmap.height()), static_cast<unsigned char *>(bitmap.getPixels()), true, quality, output);
 }
 
 bool JPEGImageEncoder::encode(const ImageData& imageData, int quality, Vector<unsigned char>* output)
 {
-    return encodePixels(imageData.size(), imageData.data()->data()->data(),
-                        false, quality, output);
+    return encodePixels(imageData.size(), imageData.data()->data()->data(), false, quality, output);
 }