author Matt Woodrow <>
Wed, 09 Feb 2011 09:35:54 +1300
changeset 62161 5ed6c4935486d1aee52f9edcd96043b0fab86fb8
parent 61310 3bdbbd75eb04786b2560dcf762c4da9172983aea
child 71521 45b7622bc948e52af00b993d08fb2a5a98471f62
permissions -rw-r--r--
Bug 586683 - Part 1 - Add resolution handling to BasicLayers. r=roc a=blocking2.0

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 * The Original Code is Mozilla Corporation code.
 * The Initial Developer of the Original Code is Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 * Contributor(s):
 *   Robert O'Callahan <>
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 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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#ifndef GFX_UTILS_H
#define GFX_UTILS_H

#include "gfxTypes.h"
#include "gfxPattern.h"
#include "gfxImageSurface.h"

class gfxDrawable;
class nsIntRegion;
struct nsIntRect;

class THEBES_API gfxUtils {
     * Premultiply or Unpremultiply aSourceSurface, writing the result
     * to aDestSurface or back into aSourceSurface if aDestSurface is null.
     * If aDestSurface is given, it must have identical format, dimensions, and
     * stride as the source.
     * If the source is not ImageFormatARGB32, no operation is performed.  If
     * aDestSurface is given, the data is copied over.
    static void PremultiplyImageSurface(gfxImageSurface *aSourceSurface,
                                        gfxImageSurface *aDestSurface = nsnull);
    static void UnpremultiplyImageSurface(gfxImageSurface *aSurface,
                                          gfxImageSurface *aDestSurface = nsnull);

     * Draw something drawable while working around limitations like bad support
     * for EXTEND_PAD, lack of source-clipping, or cairo / pixman bugs with
     * extreme user-space-to-image-space transforms.
     * The input parameters here usually come from the output of our image
     * snapping algorithm in nsLayoutUtils.cpp.
     * This method is split from nsLayoutUtils::DrawPixelSnapped to allow for
     * adjusting the parameters. For example, certain images with transparent
     * margins only have a drawable subimage. For those images, imgFrame::Draw
     * will tweak the rects and transforms that it gets from the pixel snapping
     * algorithm before passing them on to this method.
    static void DrawPixelSnapped(gfxContext*      aContext,
                                 gfxDrawable*     aDrawable,
                                 const gfxMatrix& aUserSpaceToImageSpace,
                                 const gfxRect&   aSubimage,
                                 const gfxRect&   aSourceRect,
                                 const gfxRect&   aImageRect,
                                 const gfxRect&   aFill,
                                 const gfxImageSurface::gfxImageFormat aFormat,
                                 const gfxPattern::GraphicsFilter& aFilter);

     * Clip aContext to the region aRegion.
    static void ClipToRegion(gfxContext* aContext, const nsIntRegion& aRegion);

     * Clip aContext to the region aRegion, snapping the rectangles.
    static void ClipToRegionSnapped(gfxContext* aContext, const nsIntRegion& aRegion);

     * Create a path consisting of rectangles in |aRegion|.
    static void PathFromRegion(gfxContext* aContext, const nsIntRegion& aRegion);

     * Create a path consisting of rectangles in |aRegion|, snapping the rectangles.
    static void PathFromRegionSnapped(gfxContext* aContext, const nsIntRegion& aRegion);

     * Convert image format to depth value
    static int ImageFormatToDepth(gfxASurface::gfxImageFormat aFormat);

     * If aIn can be represented exactly using an nsIntRect (i.e.
     * integer-aligned edges and coordinates in the PRInt32 range) then we
     * set aOut to that rectangle, otherwise return failure.
    static PRBool GfxRectToIntRect(const gfxRect& aIn, nsIntRect* aOut);

     * Clamp aVal to a power of kScaleResolution.
    static gfxFloat ClampToScaleFactor(gfxFloat aVal);