GraphicsContextCGWin.cpp   [plain text]

/*
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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#include "config.h"
#include "GraphicsContextCG.h"

#include "AffineTransform.h"
#include "Path.h"

#include <CoreGraphics/CGBitmapContext.h>
#include <WebKitSystemInterface/WebKitSystemInterface.h>
#include "GraphicsContextPlatformPrivateCG.h"

using namespace std;

namespace WebCore {

static CGContextRef CGContextWithHDC(HDC hdc, bool hasAlpha)
{
    HBITMAP bitmap = static_cast<HBITMAP>(GetCurrentObject(hdc, OBJ_BITMAP));

    DIBPixelData pixelData(bitmap);

    // FIXME: We can get here because we asked for a bitmap that is too big
    // when we have a tiled layer and we're compositing. In that case 
    // bmBitsPixel will be 0. This seems to be benign, so for now we will
    // exit gracefully and look at it later:
    //  https://bugs.webkit.org/show_bug.cgi?id=52041   
    // ASSERT(bitmapBits.bitsPerPixel() == 32);
    if (pixelData.bitsPerPixel() != 32)
        return 0;

    CGBitmapInfo bitmapInfo = kCGBitmapByteOrder32Little | (hasAlpha ? kCGImageAlphaPremultipliedFirst : kCGImageAlphaNoneSkipFirst);
    CGContextRef context = CGBitmapContextCreate(pixelData.buffer(), pixelData.size().width(), pixelData.size().height(), 8,
                                                 pixelData.bytesPerRow(), deviceRGBColorSpaceRef(), bitmapInfo);

    // Flip coords
    CGContextTranslateCTM(context, 0, pixelData.size().height());
    CGContextScaleCTM(context, 1, -1);
    
    // Put the HDC In advanced mode so it will honor affine transforms.
    SetGraphicsMode(hdc, GM_ADVANCED);
    
    return context;
}

GraphicsContext::GraphicsContext(HDC hdc, bool hasAlpha)
    : m_updatingControlTints(false),
      m_transparencyCount(0)
{
    platformInit(hdc, hasAlpha);
}

void GraphicsContext::platformInit(HDC hdc, bool hasAlpha)
{
    m_data = new GraphicsContextPlatformPrivate(CGContextWithHDC(hdc, hasAlpha));
    CGContextRelease(m_data->m_cgContext.get());
    m_data->m_hdc = hdc;
    setPaintingDisabled(!m_data->m_cgContext);
    if (m_data->m_cgContext) {
        // Make sure the context starts in sync with our state.
        setPlatformFillColor(fillColor(), ColorSpaceDeviceRGB);
        setPlatformStrokeColor(strokeColor(), ColorSpaceDeviceRGB);
    }
}

// FIXME: Is it possible to merge getWindowsContext and createWindowsBitmap into a single API
// suitable for all clients?
void GraphicsContext::releaseWindowsContext(HDC hdc, const IntRect& dstRect, bool supportAlphaBlend, bool mayCreateBitmap)
{
    bool createdBitmap = mayCreateBitmap && (!m_data->m_hdc || isInTransparencyLayer());
    if (!createdBitmap) {
        m_data->restore();
        return;
    }

    if (dstRect.isEmpty())
        return;

    OwnPtr<HBITMAP> bitmap = adoptPtr(static_cast<HBITMAP>(GetCurrentObject(hdc, OBJ_BITMAP)));

    DIBPixelData pixelData(bitmap.get());

    ASSERT(pixelData.bitsPerPixel() == 32);

    CGContextRef bitmapContext = CGBitmapContextCreate(pixelData.buffer(), pixelData.size().width(), pixelData.size().height(), 8,
                                                       pixelData.bytesPerRow(), deviceRGBColorSpaceRef(), kCGBitmapByteOrder32Little |
                                                       (supportAlphaBlend ? kCGImageAlphaPremultipliedFirst : kCGImageAlphaNoneSkipFirst));

    CGImageRef image = CGBitmapContextCreateImage(bitmapContext);
    CGContextDrawImage(m_data->m_cgContext.get(), dstRect, image);
    
    // Delete all our junk.
    CGImageRelease(image);
    CGContextRelease(bitmapContext);
    ::DeleteDC(hdc);
}

void GraphicsContext::drawWindowsBitmap(WindowsBitmap* image, const IntPoint& point)
{
    // FIXME: Creating CFData is non-optimal, but needed to avoid crashing when printing.  Ideally we should 
    // make a custom CGDataProvider that controls the WindowsBitmap lifetime.  see <rdar://6394455>
    RetainPtr<CFDataRef> imageData(AdoptCF, CFDataCreate(kCFAllocatorDefault, image->buffer(), image->bufferLength()));
    RetainPtr<CGDataProviderRef> dataProvider(AdoptCF, CGDataProviderCreateWithCFData(imageData.get()));
    RetainPtr<CGImageRef> cgImage(AdoptCF, CGImageCreate(image->size().width(), image->size().height(), 8, 32, image->bytesPerRow(), deviceRGBColorSpaceRef(),
                                                         kCGBitmapByteOrder32Little | kCGImageAlphaFirst, dataProvider.get(), 0, true, kCGRenderingIntentDefault));
    CGContextDrawImage(m_data->m_cgContext.get(), CGRectMake(point.x(), point.y(), image->size().width(), image->size().height()), cgImage.get());   
}

void GraphicsContext::drawFocusRing(const Path& path, int width, int offset, const Color& color)
{
    // FIXME: implement
}

// FIXME: This is nearly identical to the GraphicsContext::drawFocusRing function in GraphicsContextMac.mm.
// The code could move to GraphicsContextCG.cpp and be shared.
void GraphicsContext::drawFocusRing(const Vector<IntRect>& rects, int width, int offset, const Color& color)
{
    if (paintingDisabled())
        return;

    float radius = (width - 1) / 2.0f;
    offset += radius;
    CGColorRef colorRef = color.isValid() ? cachedCGColor(color, ColorSpaceDeviceRGB) : 0;

    CGMutablePathRef focusRingPath = CGPathCreateMutable();
    unsigned rectCount = rects.size();
    for (unsigned i = 0; i < rectCount; i++)
        CGPathAddRect(focusRingPath, 0, CGRectInset(rects[i], -offset, -offset));

    CGContextRef context = platformContext();
    CGContextSaveGState(context);

    CGContextBeginPath(context);
    CGContextAddPath(context, focusRingPath);

    wkDrawFocusRing(context, colorRef, radius);

    CGPathRelease(focusRingPath);

    CGContextRestoreGState(context);
}

// Pulled from GraphicsContextCG
static void setCGStrokeColor(CGContextRef context, const Color& color)
{
    CGFloat red, green, blue, alpha;
    color.getRGBA(red, green, blue, alpha);
    CGContextSetRGBStrokeColor(context, red, green, blue, alpha);
}

static const Color& spellingPatternColor() {
    static const Color spellingColor(255, 0, 0);
    return spellingColor;
}

static const Color& grammarPatternColor() {
    static const Color grammarColor(0, 128, 0);
    return grammarColor;
}

void GraphicsContext::drawLineForDocumentMarker(const FloatPoint& point, float width, DocumentMarkerLineStyle style)
{
    if (paintingDisabled())
        return;

    if (style != DocumentMarkerSpellingLineStyle && style != DocumentMarkerGrammarLineStyle)
        return;

    // These are the same for misspelling or bad grammar
    const int patternHeight = 3; // 3 rows
    ASSERT(cMisspellingLineThickness == patternHeight);
    const int patternWidth = 4; // 4 pixels
    ASSERT(patternWidth == cMisspellingLinePatternWidth);

    // Make sure to draw only complete dots.
    // NOTE: Code here used to shift the underline to the left and increase the width
    // to make sure everything gets underlined, but that results in drawing out of
    // bounds (e.g. when at the edge of a view) and could make it appear that the
    // space between adjacent misspelled words was underlined.
    // allow slightly more considering that the pattern ends with a transparent pixel
    float widthMod = fmodf(width, patternWidth);
    if (patternWidth - widthMod > cMisspellingLinePatternGapWidth)
        width -= widthMod;
      
    // Draw the underline
    CGContextRef context = platformContext();
    CGContextSaveGState(context);

    const Color& patternColor = style == DocumentMarkerGrammarLineStyle ? grammarPatternColor() : spellingPatternColor();
    setCGStrokeColor(context, patternColor);

    wkSetPatternPhaseInUserSpace(context, point);
    CGContextSetBlendMode(context, kCGBlendModeNormal);
    
    // 3 rows, each offset by half a pixel for blending purposes
    const CGPoint upperPoints [] = {{point.x(), point.y() + patternHeight - 2.5 }, {point.x() + width, point.y() + patternHeight - 2.5}};
    const CGPoint middlePoints [] = {{point.x(), point.y() + patternHeight - 1.5 }, {point.x() + width, point.y() + patternHeight - 1.5}};
    const CGPoint lowerPoints [] = {{point.x(), point.y() + patternHeight - 0.5 }, {point.x() + width, point.y() + patternHeight - 0.5 }};
    
    // Dash lengths for the top and bottom of the error underline are the same.
    // These are magic.
    static const float edge_dash_lengths[] = {2.0f, 2.0f};
    static const float middle_dash_lengths[] = {2.76f, 1.24f};
    static const float edge_offset = -(edge_dash_lengths[1] - 1.0f) / 2.0f;
    static const float middle_offset = -(middle_dash_lengths[1] - 1.0f) / 2.0f;

    // Line opacities.  Once again, these are magic.
    const float upperOpacity = 0.33f;
    const float middleOpacity = 0.75f;
    const float lowerOpacity = 0.88f;

    //Top line
    CGContextSetLineDash(context, edge_offset, edge_dash_lengths, WTF_ARRAY_LENGTH(edge_dash_lengths));
    CGContextSetAlpha(context, upperOpacity);
    CGContextStrokeLineSegments(context, upperPoints, 2);
 
    // Middle line
    CGContextSetLineDash(context, middle_offset, middle_dash_lengths, WTF_ARRAY_LENGTH(middle_dash_lengths));
    CGContextSetAlpha(context, middleOpacity);
    CGContextStrokeLineSegments(context, middlePoints, 2);
    
    // Bottom line
    CGContextSetLineDash(context, edge_offset, edge_dash_lengths, WTF_ARRAY_LENGTH(edge_dash_lengths));
    CGContextSetAlpha(context, lowerOpacity);
    CGContextStrokeLineSegments(context, lowerPoints, 2);

    CGContextRestoreGState(context);
}

void GraphicsContextPlatformPrivate::flush()
{
    CGContextFlush(m_cgContext.get());
}

}