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      1 /*
      2  * Copyright (C) 2008 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "GraphicsContext.h"
     28 
     29 #include "AffineTransform.h"
     30 #include "Path.h"
     31 
     32 #include <cairo-win32.h>
     33 #include "GraphicsContextPlatformPrivateCairo.h"
     34 
     35 using namespace std;
     36 
     37 namespace WebCore {
     38 
     39 static cairo_t* createCairoContextWithHDC(HDC hdc, bool hasAlpha)
     40 {
     41     // Put the HDC In advanced mode so it will honor affine transforms.
     42     SetGraphicsMode(hdc, GM_ADVANCED);
     43 
     44     cairo_surface_t* surface = 0;
     45 
     46     HBITMAP bitmap = static_cast<HBITMAP>(GetCurrentObject(hdc, OBJ_BITMAP));
     47 
     48     BITMAP info;
     49     if (!GetObject(bitmap, sizeof(info), &info))
     50         surface = cairo_win32_surface_create(hdc);
     51     else {
     52         ASSERT(info.bmBitsPixel == 32);
     53 
     54         surface = cairo_image_surface_create_for_data((unsigned char*)info.bmBits,
     55                                                CAIRO_FORMAT_ARGB32,
     56                                                info.bmWidth,
     57                                                info.bmHeight,
     58                                                info.bmWidthBytes);
     59     }
     60 
     61     cairo_t* context = cairo_create(surface);
     62     cairo_surface_destroy(surface);
     63 
     64     return context;
     65 }
     66 
     67 GraphicsContext::GraphicsContext(HDC dc, bool hasAlpha)
     68     : m_updatingControlTints(false)
     69 {
     70     platformInit(dc, hasAlpha);
     71 }
     72 
     73 void GraphicsContext::platformInit(HDC dc, bool hasAlpha)
     74 {
     75     cairo_t* cr = 0;
     76     if (dc)
     77         cr = createCairoContextWithHDC(dc, hasAlpha);
     78     else
     79         setPaintingDisabled(true);
     80 
     81     m_data = new GraphicsContextPlatformPrivateToplevel(new PlatformContextCairo(cr));
     82     m_data->m_hdc = dc;
     83     if (platformContext()->cr()) {
     84         // Make sure the context starts in sync with our state.
     85         setPlatformFillColor(fillColor(), fillColorSpace());
     86         setPlatformStrokeColor(strokeColor(), strokeColorSpace());
     87     }
     88 }
     89 
     90 static void setRGBABitmapAlpha(unsigned char* bytes, size_t length, unsigned char level)
     91 {
     92     for (size_t i = 0; i < length; i += 4)
     93         bytes[i + 3] = level;
     94 }
     95 
     96 static void drawBitmapToContext(GraphicsContextPlatformPrivate* context, cairo_t* cr, const DIBPixelData& pixelData, const IntSize& translate)
     97 {
     98     // Need to make a cairo_surface_t out of the bitmap's pixel buffer and then draw
     99     // it into our context.
    100     cairo_surface_t* surface = cairo_image_surface_create_for_data(pixelData.buffer(),
    101                                                                    CAIRO_FORMAT_ARGB32,
    102                                                                    pixelData.size().width(),
    103                                                                    pixelData.size().height(),
    104                                                                    pixelData.bytesPerRow());
    105 
    106     // Flip the target surface so that when we set the srcImage as
    107     // the surface it will draw right-side-up.
    108     cairo_save(cr);
    109     cairo_translate(cr, static_cast<double>(translate.width()), static_cast<double>(translate.height()));
    110     cairo_scale(cr, 1, -1);
    111     cairo_set_source_surface(cr, surface, 0, 0);
    112 
    113     if (context->layers.size())
    114         cairo_paint_with_alpha(cr, context->layers.last());
    115     else
    116         cairo_paint(cr);
    117 
    118     // Delete all our junk.
    119     cairo_surface_destroy(surface);
    120     cairo_restore(cr);
    121 }
    122 
    123 void GraphicsContext::releaseWindowsContext(HDC hdc, const IntRect& dstRect, bool supportAlphaBlend, bool mayCreateBitmap)
    124 {
    125     bool createdBitmap = mayCreateBitmap && (!m_data->m_hdc || inTransparencyLayer());
    126     if (!hdc || !createdBitmap) {
    127         m_data->restore();
    128         return;
    129     }
    130 
    131     if (dstRect.isEmpty())
    132         return;
    133 
    134     OwnPtr<HBITMAP> bitmap = adoptPtr(static_cast<HBITMAP>(GetCurrentObject(hdc, OBJ_BITMAP)));
    135 
    136     DIBPixelData pixelData(bitmap.get());
    137     ASSERT(pixelData.bitsPerPixel() == 32);
    138 
    139     // If this context does not support alpha blending, then it may have
    140     // been drawn with GDI functions which always set the alpha channel
    141     // to zero. We need to manually set the bitmap to be fully opaque.
    142     unsigned char* bytes = reinterpret_cast<unsigned char*>(pixelData.buffer());
    143     if (!supportAlphaBlend)
    144         setRGBABitmapAlpha(bytes, pixelData.size().height() * pixelData.bytesPerRow(), 255);
    145 
    146     drawBitmapToContext(m_data, platformContext()->cr(), pixelData, IntSize(dstRect.x(), dstRect.height() + dstRect.y()));
    147 
    148     ::DeleteDC(hdc);
    149 }
    150 
    151 void GraphicsContext::drawWindowsBitmap(WindowsBitmap* bitmap, const IntPoint& point)
    152 {
    153     drawBitmapToContext(m_data, platformContext()->cr(), bitmap->windowsDIB(), IntSize(point.x(), bitmap->size().height() + point.y()));
    154 }
    155 
    156 void GraphicsContextPlatformPrivate::syncContext(cairo_t* cr)
    157 {
    158     if (!cr)
    159        return;
    160 
    161     cairo_surface_t* surface = cairo_get_target(cr);
    162     m_hdc = cairo_win32_surface_get_dc(surface);
    163 
    164     SetGraphicsMode(m_hdc, GM_ADVANCED); // We need this call for themes to honor world transforms.
    165 }
    166 
    167 void GraphicsContextPlatformPrivate::flush()
    168 {
    169     cairo_surface_t* surface = cairo_win32_surface_create(m_hdc);
    170     cairo_surface_flush(surface);
    171     cairo_surface_destroy(surface);
    172 }
    173 
    174 }
    175