Support for non-DOM canvases/contexts (backed by bitaps).

runtime/embedders/openglui/common/canvas_context.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "embedders/openglui/common/canvas_context.h"
 
 #include <ctype.h>
 #include <string.h>
 
 #include "embedders/openglui/common/support.h"
 
-CanvasContext::CanvasContext(int16_t widthp, int16_t heightp)
+// TODO(gram): this should be dynamic.
+#define MAX_CONTEXTS 16
+CanvasContext* contexts[MAX_CONTEXTS] = { 0 };
+
+CanvasContext* Context2D(int handle) {
+  if (handle < 0 || handle >= MAX_CONTEXTS) {
+    return NULL;
+  }
+  return contexts[handle];
+}
+
+CanvasContext::CanvasContext(int handle, int16_t widthp, int16_t heightp)
   : canvas_(NULL),
     width_(widthp),
     height_(heightp),
     imageSmoothingEnabled_(true),
     state_(NULL) {
+  if (handle == 0) {
+    canvas_ = graphics->CreateDisplayCanvas();
+  } else {
+    canvas_ = graphics->CreateBitmapCanvas(widthp, heightp);
+  }
+  state_ = new CanvasState(canvas_);
+  contexts[handle] = this;
 }
 
 CanvasContext::~CanvasContext() {
   delete state_;
   delete canvas_;
 }
 
-void CanvasContext::Create() {
-  canvas_ = graphics->CreateCanvas();
-  state_ = new CanvasState(canvas_);
-}
-
 void CanvasContext::DrawImage(const char* src_url,
                               int sx, int sy,
                               bool has_src_dimensions, int sw, int sh,
                               int dx, int dy,
                               bool has_dst_dimensions, int dw, int dh) {
   SkBitmap bm;
-  // TODO(gram): We need a way to remap URLs to local file names.
-  // For now I am just using the characters after the last '/'.
-  // Note also that if we want to support URLs and network fetches,
-  // then we introduce more complexity; this can't just be an URL.
-  int pos = strlen(src_url);
-  while (--pos >= 0 && src_url[pos] != '/');
-  const char *path = src_url + pos + 1;
-  if (!SkImageDecoder::DecodeFile(path, &bm)) {
-    LOGI("Image decode of %s failed", path);
+  if (strncmp(src_url, "context2d://", 12) == 0) {
+    int handle = atoi(src_url + 12);
+    CanvasContext* otherContext = Context2D(handle);
+    SkDevice* device = otherContext->canvas_->getDevice();
+    bm = device->accessBitmap(false);
   } else {
-    LOGI("Decode image: width=%d,height=%d", bm.width(), bm.height());
-    if (!has_src_dimensions) {
-      sw = bm.width();
-      sh = bm.height();
+    // TODO(gram): We need a way to remap URLs to local file names.
+    // For now I am just using the characters after the last '/'.
+    // Note also that if we want to support URLs and network fetches,
+    // then we introduce more complexity; this can't just be an URL.
+    int pos = strlen(src_url);
+    while (--pos >= 0 && src_url[pos] != '/');
+    const char *path = src_url + pos + 1;
+    if (!SkImageDecoder::DecodeFile(path, &bm)) {
+      LOGI("Image decode of %s failed", path);
+      return;
+    } else {
+      LOGI("Decode image: width=%d,height=%d", bm.width(), bm.height());
     }
-    if (!has_dst_dimensions) {
-      dw = bm.width();
-      dh = bm.height();
-    }
-    state_->DrawImage(bm, sx, sy, sw, sh, dx, dy, dw, dh);
   }
+  if (!has_src_dimensions) {
+    sw = bm.width();
+    sh = bm.height();
+  }
+  if (!has_dst_dimensions) {
+    dw = bm.width();
+    dh = bm.height();
+  }
+  state_->DrawImage(bm, sx, sy, sw, sh, dx, dy, dw, dh);
 }
 
 void CanvasContext::ClearRect(float left, float top,
                               float width, float height) {
   SkPaint paint;
   paint.setStyle(SkPaint::kFill_Style);
   paint.setColor(0xFFFFFFFF);
   canvas_->drawRectCoords(left, top, left + width, top + height, paint);
 }