gfx/thebes/gfxWindowsNativeDrawing.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef _GFXWINDOWSNATIVEDRAWING_H_
   7 #define _GFXWINDOWSNATIVEDRAWING_H_
   8
   9 #include <windows.h>
  10
  11 #include "gfxContext.h"
  12 #include "gfxWindowsSurface.h"
  13
  14 class gfxWindowsNativeDrawing {
  15 public:
  16
  17     /* Flags for notifying this class what kind of operations the native
  18      * drawing supports
  19      */
  20
  21     enum {
  22         /* Whether the native drawing can draw to a surface of content COLOR_ALPHA */
  23         CAN_DRAW_TO_COLOR_ALPHA    = 1 << 0,
  24         CANNOT_DRAW_TO_COLOR_ALPHA = 0 << 0,
  25
  26         /* Whether the native drawing can be scaled using SetWorldTransform */
  27         CAN_AXIS_ALIGNED_SCALE     = 1 << 1,
  28         CANNOT_AXIS_ALIGNED_SCALE  = 0 << 1,
  29
  30         /* Whether the native drawing can be both scaled and rotated arbitrarily using SetWorldTransform */
  31         CAN_COMPLEX_TRANSFORM      = 1 << 2,
  32         CANNOT_COMPLEX_TRANSFORM   = 0 << 2,
  33
  34         /* If we have to do transforms with cairo, should we use nearest-neighbour filtering? */
  35         DO_NEAREST_NEIGHBOR_FILTERING = 1 << 3,
  36         DO_BILINEAR_FILTERING         = 0 << 3
  37     };
  38
  39     /* Create native win32 drawing for a rectangle bounded by
  40      * nativeRect.
  41      *
  42      * Typical usage looks like:
  43      *
  44      *   gfxWindowsNativeDrawing nativeDraw(ctx, destGfxRect, capabilities);
  45      *   do {
  46      *     HDC dc = nativeDraw.BeginNativeDrawing();
  47      *     if (!dc)
  48      *       return NS_ERROR_FAILURE;
  49      *
  50      *     RECT winRect;
  51      *     nativeDraw.TransformToNativeRect(rect, winRect);
  52      *
  53      *       ... call win32 operations on HDC to draw to winRect ...
  54      *
  55      *     nativeDraw.EndNativeDrawing();
  56      *   } while (nativeDraw.ShouldRenderAgain());
  57      *   nativeDraw.PaintToContext();
  58      */
  59     gfxWindowsNativeDrawing(gfxContext *ctx,
  60                             const gfxRect& nativeRect,
  61                             uint32_t nativeDrawFlags = CANNOT_DRAW_TO_COLOR_ALPHA |
  62                                                        CANNOT_AXIS_ALIGNED_SCALE |
  63                                                        CANNOT_COMPLEX_TRANSFORM |
  64                                                        DO_BILINEAR_FILTERING);
  65
  66     /* Returns a HDC which may be used for native drawing.  This HDC is valid
  67      * until EndNativeDrawing is called; if it is used for drawing after that time,
  68      * the result is undefined. */
  69     HDC BeginNativeDrawing();
  70
  71     /* Transform the native rect into something valid for rendering
  72      * to the HDC.  This may or may not change RECT, depending on
  73      * whether SetWorldTransform is used or not. */
  74     void TransformToNativeRect(const gfxRect& r, RECT& rout);
  75
  76     /* Marks the end of native drawing */
  77     void EndNativeDrawing();
  78
  79     /* Returns true if the native drawing should be executed again */
  80     bool ShouldRenderAgain();
  81
  82     /* Returns true if double pass alpha extraction is taking place. */
  83     bool IsDoublePass();
  84
  85     /* Places the result to the context, if necessary */
  86     void PaintToContext();
  87
  88 private:
  89
  90     nsRefPtr<gfxContext> mContext;
  91     gfxRect mNativeRect;
  92     uint32_t mNativeDrawFlags;
  93
  94     // what state the rendering is in
  95     uint8_t mRenderState;
  96
  97     gfxPoint mDeviceOffset;
  98     nsRefPtr<gfxPattern> mBlackPattern, mWhitePattern;
  99
 100     enum TransformType {
 101         TRANSLATION_ONLY,
 102         AXIS_ALIGNED_SCALE,
 103         COMPLEX
 104     };
 105
 106     TransformType mTransformType;
 107     gfxPoint mTranslation;
 108     gfxSize mScale;
 109     XFORM mWorldTransform;
 110
 111     // saved state
 112     nsRefPtr<gfxWindowsSurface> mWinSurface, mBlackSurface, mWhiteSurface;
 113     HDC mDC;
 114     XFORM mOldWorldTransform;
 115     POINT mOrigViewportOrigin;
 116     gfxIntSize mTempSurfaceSize;
 117 };
 118
 119 #endif