1 files changed, 153 insertions, 0 deletions
diff --git a/WebCore/platform/image-encoders/skia/JPEGImageEncoder.cpp b/WebCore/platform/image-encoders/skia/JPEGImageEncoder.cpp
new file mode 100644
index 0000000..d4e1481
--- /dev/null
+++ b/WebCore/platform/image-encoders/skia/JPEGImageEncoder.cpp
@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2010, Google Inc. All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "JPEGImageEncoder.h"
+
+#include "IntSize.h"
+#include "SkBitmap.h"
+#include "SkUnPreMultiply.h"
+#include "SkColorPriv.h"
+extern "C" {
+#include <stdio.h> // jpeglib.h needs stdio.h FILE
+#include "jpeglib.h"
+#include <setjmp.h>
+}
+
+namespace WebCore {
+
+struct JPEGOutputBuffer : public jpeg_destination_mgr {
+    Vector<unsigned char>* output;
+    Vector<unsigned char> buffer;
+};
+
+static void prepareOutput(j_compress_ptr cinfo)
+{
+    JPEGOutputBuffer* out = static_cast<JPEGOutputBuffer*>(cinfo->dest);
+    const size_t internalBufferSize = 8192;
+    out->buffer.resize(internalBufferSize);
+    out->next_output_byte = out->buffer.data();
+    out->free_in_buffer = out->buffer.size();
+}
+
+static boolean writeOutput(j_compress_ptr cinfo)
+{
+    JPEGOutputBuffer* out = static_cast<JPEGOutputBuffer*>(cinfo->dest);
+    out->output->append(out->buffer.data(), out->buffer.size());
+    out->next_output_byte = out->buffer.data();
+    out->free_in_buffer = out->buffer.size();
+    return TRUE;
+}
+
+static void finishOutput(j_compress_ptr cinfo)
+{
+    JPEGOutputBuffer* out = static_cast<JPEGOutputBuffer*>(cinfo->dest);
+    const size_t size = out->buffer.size() - out->free_in_buffer;
+    out->output->append(out->buffer.data(), size);
+}
+
+static void handleError(j_common_ptr common)
+{
+    jmp_buf* jumpBufferPtr = static_cast<jmp_buf*>(common->client_data);
+    longjmp(*jumpBufferPtr, -1);
+}
+
+// FIXME: is alpha unpremultiplication correct, or should the alpha channel
+// be ignored? See bug http://webkit.org/b/40147.
+void preMultipliedBGRAtoRGB(const SkPMColor* input, unsigned int pixels, unsigned char* output)
+{
+    static const SkUnPreMultiply::Scale* scale = SkUnPreMultiply::GetScaleTable();
+
+    for (; pixels-- > 0; ++input) {
+        const unsigned alpha = SkGetPackedA32(*input);
+        if ((alpha != 0) && (alpha != 255)) {
+            *output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedR32(*input));
+            *output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedG32(*input));
+            *output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedB32(*input));
+        } else {
+            *output++ = SkGetPackedR32(*input);
+            *output++ = SkGetPackedG32(*input);
+            *output++ = SkGetPackedB32(*input);
+        }
+    }
+}
+
+bool JPEGImageEncoder::encode(const SkBitmap& bitmap, int quality, Vector<unsigned char>* output)
+{
+    if (bitmap.config() != SkBitmap::kARGB_8888_Config)
+        return false; // Only support ARGB 32 bpp skia bitmaps.
+
+    SkAutoLockPixels bitmapLock(bitmap);
+    IntSize imageSize(bitmap.width(), bitmap.height());
+    imageSize.clampNegativeToZero();
+    JPEGOutputBuffer destination;
+    destination.output = output;
+    Vector<JSAMPLE> row;
+
+    jpeg_compress_struct cinfo;
+    jpeg_error_mgr error;
+    cinfo.err = jpeg_std_error(&error);
+    error.error_exit = handleError;
+    jmp_buf jumpBuffer;
+    cinfo.client_data = &jumpBuffer;
+
+    if (setjmp(jumpBuffer)) {
+        jpeg_destroy_compress(&cinfo);
+        return false;
+    }
+
+    jpeg_create_compress(&cinfo);
+    cinfo.dest = &destination;
+    cinfo.dest->init_destination = prepareOutput;
+    cinfo.dest->empty_output_buffer = writeOutput;
+    cinfo.dest->term_destination = finishOutput;
+    cinfo.image_height = imageSize.height();
+    cinfo.image_width = imageSize.width();
+    cinfo.in_color_space = JCS_RGB;
+    cinfo.input_components = 3;
+
+    jpeg_set_defaults(&cinfo);
+    jpeg_set_quality(&cinfo, quality, TRUE);
+    jpeg_start_compress(&cinfo, TRUE);
+
+    const SkPMColor* pixels = static_cast<SkPMColor*>(bitmap.getPixels());
+    row.resize(cinfo.image_width * cinfo.input_components);
+    while (cinfo.next_scanline < cinfo.image_height) {
+        preMultipliedBGRAtoRGB(pixels, cinfo.image_width, row.data());
+        jpeg_write_scanlines(&cinfo, row.dataSlot(), 1);
+        pixels += cinfo.image_width;
+    }
+
+    jpeg_finish_compress(&cinfo);
+    jpeg_destroy_compress(&cinfo);
+    return true;
+}
+
+} // namespace WebCore