add SkCanvas constructor that explicitly creates no_config with dimensions

BUG=skia:
R=scroggo@google.com, halcanary@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/137833016

git-svn-id: http://skia.googlecode.com/svn/trunk@13272 2bbb7eff-a529-9590-31e7-b0007b416f81

7 files changed, 36 insertions, 37 deletions

diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 5a5cc65f0b..c98ad996f0 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -49,8 +49,19 @@ class SK_API SkCanvas : public SkRefCnt {
 public:
     SK_DECLARE_INST_COUNT(SkCanvas)
 
+    /**
+     *  Creates an empty canvas with no backing device/pixels, and zero
+     *  dimensions.
+     */
     SkCanvas();
 
+    /**
+     *  Creates a canvas of the specified dimensions, but explicitly not backed
+     *  by any device/pixels. Typically this use used by subclasses who handle
+     *  the draw calls in some other way.
+     */
+    SkCanvas(int width, int height);
+
     /** Construct a canvas with the specified device to draw into.
 
         @param device   Specifies a device for the canvas to draw into.
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index a5fa30ff2d..45c196448d 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -505,21 +505,34 @@ SkBaseDevice* SkCanvas::init(SkBaseDevice* device) {
 }
 
 SkCanvas::SkCanvas()
-: fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage)) {
+    : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage))
+{
     inc_canvas();
-
+    
     this->init(NULL);
 }
 
+SkCanvas::SkCanvas(int width, int height)
+    : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage))
+{
+    inc_canvas();
+    
+    SkBitmap bitmap;
+    bitmap.setConfig(SkBitmap::kNo_Config, width, height);
+    this->init(SkNEW_ARGS(SkBitmapDevice, (bitmap)))->unref();
+}
+
 SkCanvas::SkCanvas(SkBaseDevice* device)
-        : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage)) {
+    : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage))
+{
     inc_canvas();
 
     this->init(device);
 }
 
 SkCanvas::SkCanvas(const SkBitmap& bitmap)
-        : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage)) {
+    : fMCStack(sizeof(MCRec), fMCRecStorage, sizeof(fMCRecStorage))
+{
     inc_canvas();
 
     this->init(SkNEW_ARGS(SkBitmapDevice, (bitmap)))->unref();
diff --git a/src/utils/SkDumpCanvas.cpp b/src/utils/SkDumpCanvas.cpp
index dabf0d7989..5f3a572ab9 100644
--- a/src/utils/SkDumpCanvas.cpp
+++ b/src/utils/SkDumpCanvas.cpp
@@ -163,15 +163,9 @@ static void toString(const void* text, size_t byteLen, SkPaint::TextEncoding enc
 
 ///////////////////////////////////////////////////////////////////////////////
 
-static SkBitmap make_wideopen_bm() {
-    static const int WIDE_OPEN = 16384;
+#define WIDE_OPEN   16384
 
-    SkBitmap bm;
-    bm.setConfig(SkBitmap::kNo_Config, WIDE_OPEN, WIDE_OPEN);
-    return bm;
-}
-
-SkDumpCanvas::SkDumpCanvas(Dumper* dumper) : INHERITED(make_wideopen_bm()) {
+SkDumpCanvas::SkDumpCanvas(Dumper* dumper) : INHERITED(WIDE_OPEN, WIDE_OPEN) {
     fNestLevel = 0;
     SkSafeRef(dumper);
     fDumper = dumper;
diff --git a/src/utils/SkLuaCanvas.cpp b/src/utils/SkLuaCanvas.cpp
index 0136231ce1..7f127403ae 100644
--- a/src/utils/SkLuaCanvas.cpp
+++ b/src/utils/SkLuaCanvas.cpp
@@ -73,14 +73,8 @@ void SkLuaCanvas::pushThis() {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-static SkBitmap make_bm(int width, int height) {
-    SkBitmap bm;
-    bm.setConfig(SkBitmap::kNo_Config, width, height);
-    return bm;
-}
-
 SkLuaCanvas::SkLuaCanvas(int width, int height, lua_State* L, const char func[])
-    : INHERITED(make_bm(width, height))
+    : INHERITED(width, height)
     , fL(L)
     , fFunc(func) {
 }
diff --git a/src/utils/SkNWayCanvas.cpp b/src/utils/SkNWayCanvas.cpp
index da8bdb6f41..831d7bf6cf 100644
--- a/src/utils/SkNWayCanvas.cpp
+++ b/src/utils/SkNWayCanvas.cpp
@@ -7,14 +7,8 @@
  */
 #include "SkNWayCanvas.h"
 
-static SkBitmap make_noconfig_bm(int width, int height) {
-    SkBitmap bm;
-    bm.setConfig(SkBitmap::kNo_Config, width, height);
-    return bm;
-}
-
 SkNWayCanvas::SkNWayCanvas(int width, int height)
-        : INHERITED(make_noconfig_bm(width, height)) {}
+        : INHERITED(width, height) {}
 
 SkNWayCanvas::~SkNWayCanvas() {
     this->removeAll();
diff --git a/src/utils/debugger/SkDebugCanvas.cpp b/src/utils/debugger/SkDebugCanvas.cpp
index 1c3e26e643..32a6570954 100644
--- a/src/utils/debugger/SkDebugCanvas.cpp
+++ b/src/utils/debugger/SkDebugCanvas.cpp
@@ -14,14 +14,8 @@
 #include "SkDevice.h"
 #include "SkXfermode.h"
 
-static SkBitmap make_noconfig_bm(int width, int height) {
-    SkBitmap bm;
-    bm.setConfig(SkBitmap::kNo_Config, width, height);
-    return bm;
-}
-
 SkDebugCanvas::SkDebugCanvas(int width, int height)
-        : INHERITED(make_noconfig_bm(width, height))
+        : INHERITED(width, height)
         , fWidth(width)
         , fHeight(height)
         , fFilter(false)
diff --git a/tests/PictureTest.cpp b/tests/PictureTest.cpp
index 5aaf73bdfb..7665b13d7e 100644
--- a/tests/PictureTest.cpp
+++ b/tests/PictureTest.cpp
@@ -922,8 +922,8 @@ static void test_clip_bound_opt(skiatest::Reporter* reporter) {
  */
 class ClipCountingCanvas : public SkCanvas {
 public:
-    explicit ClipCountingCanvas(SkBaseDevice* device)
-        : SkCanvas(device)
+    explicit ClipCountingCanvas(int width, int height)
+        : INHERITED(width, height)
         , fClipCount(0){
     }
 
@@ -965,8 +965,7 @@ static void test_clip_expansion(skiatest::Reporter* reporter) {
     p.setColor(SK_ColorBLUE);
     canvas->drawPaint(p);
 
-    SkBitmapDevice testDevice(SkBitmap::kNo_Config, 10, 10);
-    ClipCountingCanvas testCanvas(&testDevice);
+    ClipCountingCanvas testCanvas(10, 10);
     picture.draw(&testCanvas);
 
     // Both clips should be present on playback.