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author | brettw@google.com <brettw@google.com@0039d316-1c4b-4281-b951-d872f2087c98> | 2008-11-21 23:03:56 +0000 |
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committer | brettw@google.com <brettw@google.com@0039d316-1c4b-4281-b951-d872f2087c98> | 2008-11-21 23:03:56 +0000 |
commit | 156f2c0e187c0283f026fd356a4b682d4b4eaaa1 (patch) | |
tree | 209d254abb43d9ff2cb9a904dd16eed00a85bfb4 /skia/ext/platform_canvas_win.h | |
parent | bd2e63eed24e8c097be6ea3fb46aa354c638e88e (diff) | |
download | chromium_src-156f2c0e187c0283f026fd356a4b682d4b4eaaa1.zip chromium_src-156f2c0e187c0283f026fd356a4b682d4b4eaaa1.tar.gz chromium_src-156f2c0e187c0283f026fd356a4b682d4b4eaaa1.tar.bz2 |
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
Diffstat (limited to 'skia/ext/platform_canvas_win.h')
-rw-r--r-- | skia/ext/platform_canvas_win.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/skia/ext/platform_canvas_win.h b/skia/ext/platform_canvas_win.h new file mode 100644 index 0000000..c3f42a3 --- /dev/null +++ b/skia/ext/platform_canvas_win.h @@ -0,0 +1,202 @@ +// 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_ + |