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authorbrettw@google.com <brettw@google.com@0039d316-1c4b-4281-b951-d872f2087c98>2008-11-21 23:03:56 +0000
committerbrettw@google.com <brettw@google.com@0039d316-1c4b-4281-b951-d872f2087c98>2008-11-21 23:03:56 +0000
commit156f2c0e187c0283f026fd356a4b682d4b4eaaa1 (patch)
tree209d254abb43d9ff2cb9a904dd16eed00a85bfb4 /skia/ext/platform_canvas_win.h
parentbd2e63eed24e8c097be6ea3fb46aa354c638e88e (diff)
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Move skia extensions from the port to skia/ext for Windows only. Fixed the
include guards of the moved files, but nothing else. Review URL: http://codereview.chromium.org/11568 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@5861 0039d316-1c4b-4281-b951-d872f2087c98
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diff --git a/skia/ext/platform_canvas_win.h b/skia/ext/platform_canvas_win.h
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+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SKIA_EXT_PLATFORM_CANVAS_WIN_H_
+#define SKIA_EXT_PLATFORM_CANVAS_WIN_H_
+
+#include <windows.h>
+
+#include "base/basictypes.h"
+#include "skia/ext/platform_device_win.h"
+
+#include "SkCanvas.h"
+
+namespace gfx {
+
+// This class is a specialization of the regular SkCanvas that is designed to
+// work with a gfx::PlatformDevice to manage platform-specific drawing. It
+// allows using both Skia operations and platform-specific operations.
+class PlatformCanvasWin : public SkCanvas {
+ public:
+ // Set is_opaque if you are going to erase the bitmap and not use
+ // transparency: this will enable some optimizations. The shared_section
+ // parameter is passed to gfx::PlatformDevice::create. See it for details.
+ //
+ // If you use the version with no arguments, you MUST call initialize()
+ PlatformCanvasWin();
+ PlatformCanvasWin(int width, int height, bool is_opaque);
+ PlatformCanvasWin(int width, int height, bool is_opaque,
+ HANDLE shared_section);
+ virtual ~PlatformCanvasWin();
+
+ // For two-part init, call if you use the no-argument constructor above. Note
+ // that we want this to optionally match the Linux initialize if you only
+ // pass 3 arguments, hence the evil default argument.
+ bool initialize(int width, int height, bool is_opaque,
+ HANDLE shared_section = NULL);
+
+ // These calls should surround calls to platform drawing routines, the DC
+ // returned by beginPlatformPaint is the DC that can be used to draw into.
+ // Call endPlatformPaint when you are done and want to use Skia operations
+ // again; this will synchronize the bitmap to Windows.
+ virtual HDC beginPlatformPaint();
+ virtual void endPlatformPaint();
+
+ // Returns the platform device pointer of the topmost rect with a non-empty
+ // clip. In practice, this is usually either the top layer or nothing, since
+ // we usually set the clip to new layers when we make them.
+ //
+ // If there is no layer that is not all clipped out, this will return a
+ // dummy device so callers do not have to check. If you are concerned about
+ // performance, check the clip before doing any painting.
+ //
+ // This is different than SkCanvas' getDevice, because that returns the
+ // bottommost device.
+ //
+ // Danger: the resulting device should not be saved. It will be invalidated
+ // by the next call to save() or restore().
+ PlatformDeviceWin& getTopPlatformDevice() const;
+
+ protected:
+ // Creates a device store for use by the canvas. We override this so that
+ // the device is always our own so we know that we can use GDI operations
+ // on it. Simply calls into createPlatformDevice().
+ virtual SkDevice* createDevice(SkBitmap::Config, int width, int height,
+ bool is_opaque, bool isForLayer);
+
+ // Creates a device store for use by the canvas. By default, it creates a
+ // BitmapPlatformDeviceWin. Can be overridden to change the object type.
+ virtual SkDevice* createPlatformDevice(int width, int height, bool is_opaque,
+ HANDLE shared_section);
+
+ private:
+ // Unimplemented.
+ virtual SkDevice* setBitmapDevice(const SkBitmap& bitmap);
+
+ // Disallow copy and assign.
+ PlatformCanvasWin(const PlatformCanvasWin&);
+ PlatformCanvasWin& operator=(const PlatformCanvasWin&);
+};
+
+// A class designed to help with WM_PAINT operations on Windows. It will
+// do BeginPaint/EndPaint on init/destruction, and will create the bitmap and
+// canvas with the correct size and transform for the dirty rect. The bitmap
+// will be automatically painted to the screen on destruction.
+//
+// You MUST call isEmpty before painting to determine if anything needs
+// painting. Sometimes the dirty rect can actually be empty, and this makes
+// the bitmap functions we call unhappy. The caller should not paint in this
+// case.
+//
+// Therefore, all you need to do is:
+// case WM_PAINT: {
+// gfx::PlatformCanvasWinPaint canvas(hwnd);
+// if (!canvas.isEmpty()) {
+// ... paint to the canvas ...
+// }
+// return 0;
+// }
+template <class T>
+class CanvasPaintT : public T {
+ public:
+ CanvasPaintT(HWND hwnd) : hwnd_(hwnd), paint_dc_(NULL), for_paint_(true) {
+ memset(&ps_, 0, sizeof(ps_));
+ initPaint(true);
+ }
+
+ CanvasPaintT(HWND hwnd, bool opaque) : hwnd_(hwnd), paint_dc_(NULL),
+ for_paint_(true) {
+ memset(&ps_, 0, sizeof(ps_));
+ initPaint(opaque);
+ }
+
+ // Creates a CanvasPaintT for the specified region that paints to the
+ // specified dc. This does NOT do BeginPaint/EndPaint.
+ CanvasPaintT(HDC dc, bool opaque, int x, int y, int w, int h)
+ : hwnd_(NULL),
+ paint_dc_(dc),
+ for_paint_(false) {
+ memset(&ps_, 0, sizeof(ps_));
+ ps_.rcPaint.left = x;
+ ps_.rcPaint.right = x + w;
+ ps_.rcPaint.top = y;
+ ps_.rcPaint.bottom = y + h;
+ init(opaque);
+ }
+
+
+ virtual ~CanvasPaintT() {
+ if (!isEmpty()) {
+ restoreToCount(1);
+ // Commit the drawing to the screen
+ getTopPlatformDevice().drawToHDC(paint_dc_,
+ ps_.rcPaint.left, ps_.rcPaint.top,
+ NULL);
+ }
+ if (for_paint_)
+ EndPaint(hwnd_, &ps_);
+ }
+
+ // Returns true if the invalid region is empty. The caller should call this
+ // function to determine if anything needs painting.
+ bool isEmpty() const {
+ return ps_.rcPaint.right - ps_.rcPaint.left == 0 ||
+ ps_.rcPaint.bottom - ps_.rcPaint.top == 0;
+ }
+
+ // Use to access the Windows painting parameters, especially useful for
+ // getting the bounding rect for painting: paintstruct().rcPaint
+ const PAINTSTRUCT& paintStruct() const {
+ return ps_;
+ }
+
+ // Returns the DC that will be painted to
+ HDC paintDC() const {
+ return paint_dc_;
+ }
+
+ protected:
+ HWND hwnd_;
+ HDC paint_dc_;
+ PAINTSTRUCT ps_;
+
+ private:
+ void initPaint(bool opaque) {
+ paint_dc_ = BeginPaint(hwnd_, &ps_);
+
+ init(opaque);
+ }
+
+ void init(bool opaque) {
+ // FIXME(brettw) for ClearType, we probably want to expand the bounds of
+ // painting by one pixel so that the boundaries will be correct (ClearType
+ // text can depend on the adjacent pixel). Then we would paint just the
+ // inset pixels to the screen.
+ const int width = ps_.rcPaint.right - ps_.rcPaint.left;
+ const int height = ps_.rcPaint.bottom - ps_.rcPaint.top;
+ if (!initialize(width, height, opaque, NULL)) {
+ // Cause a deliberate crash;
+ *(char*) 0 = 0;
+ }
+
+ // This will bring the canvas into the screen coordinate system for the
+ // dirty rect
+ translate(SkIntToScalar(-ps_.rcPaint.left),
+ SkIntToScalar(-ps_.rcPaint.top));
+ }
+
+ // If true, this canvas was created for a BeginPaint.
+ const bool for_paint_;
+
+ // Disallow copy and assign.
+ CanvasPaintT(const CanvasPaintT&);
+ CanvasPaintT& operator=(const CanvasPaintT&);
+};
+
+typedef CanvasPaintT<PlatformCanvasWin> PlatformCanvasWinPaint;
+
+} // namespace gfx
+
+#endif // SKIA_EXT_PLATFORM_CANVAS_WIN_H_
+