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      1 /*
      2  * Copyright 2006, The Android Open Source Project
      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  *  * Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  *  * 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 THE COPYRIGHT HOLDERS ``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 THE COPYRIGHT OWNER 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 "Gradient.h"
     28 
     29 #include "android_graphics.h"
     30 #include "CSSParser.h"
     31 #include "GraphicsContext.h"
     32 #include "NotImplemented.h"
     33 #include "SkCanvas.h"
     34 #include "SkColorShader.h"
     35 #include "SkGradientShader.h"
     36 #include "SkPaint.h"
     37 
     38 class PlatformGradientRec {
     39 public:
     40     PlatformGradientRec() : m_shader(NULL) {}
     41     ~PlatformGradientRec() { m_shader->safeUnref(); }
     42 
     43     SkShader*           m_shader;
     44     SkShader::TileMode  m_tileMode;
     45     int                 m_colorCountWhenShaderWasBuilt;
     46 };
     47 
     48 namespace WebCore {
     49 
     50 void Gradient::platformDestroy()
     51 {
     52     delete m_gradient;
     53     m_gradient = 0;
     54 }
     55 
     56 static U8CPU F2B(float x)
     57 {
     58     return (int)(x * 255);
     59 }
     60 
     61 SkShader* Gradient::getShader(SkShader::TileMode mode)
     62 {
     63     if (NULL == m_gradient)
     64         m_gradient = new PlatformGradientRec;
     65     else if (mode == m_gradient->m_tileMode)
     66         return m_gradient->m_shader;
     67 
     68     // need to ensure that the m_stops array is sorted. We call getColor()
     69     // which, as a side effect, does the sort.
     70     // TODO: refactor Gradient.h to formally expose a sort method
     71     {
     72         float r, g, b, a;
     73         this->getColor(0, &r, &g, &b, &a);
     74     }
     75 
     76     SkPoint pts[2] = { m_p0, m_p1 };    // convert to SkPoint
     77 
     78     const size_t count = m_stops.size();
     79     SkAutoMalloc    storage(count * (sizeof(SkColor) + sizeof(SkScalar)));
     80     SkColor*        colors = (SkColor*)storage.get();
     81     SkScalar*       pos = (SkScalar*)(colors + count);
     82 
     83     Vector<ColorStop>::iterator iter = m_stops.begin();
     84     for (int i = 0; iter != m_stops.end(); i++) {
     85         pos[i] = SkFloatToScalar(iter->stop);
     86         colors[i] = SkColorSetARGB(F2B(iter->alpha), F2B(iter->red),
     87                                    F2B(iter->green), F2B(iter->blue));
     88         ++iter;
     89     }
     90 
     91     SkShader* s;
     92     if (m_radial)
     93         s = SkGradientShader::CreateTwoPointRadial(pts[0],
     94                                                    SkFloatToScalar(m_r0),
     95                                                    pts[1],
     96                                                    SkFloatToScalar(m_r1),
     97                                                    colors, pos, count, mode);
     98     else
     99         s = SkGradientShader::CreateLinear(pts, colors, pos, count, mode);
    100 
    101     if (NULL == s)
    102         s = new SkColorShader(0);
    103 
    104     // zap our previous shader, if present
    105     m_gradient->m_shader->safeUnref();
    106     m_gradient->m_shader = s;
    107     m_gradient->m_tileMode = mode;
    108     SkMatrix matrix = m_gradientSpaceTransformation;
    109     s->setLocalMatrix(matrix);
    110 
    111     return s;
    112 }
    113 
    114 void Gradient::fill(GraphicsContext* context, const FloatRect& rect)
    115 {
    116     SkRect r;
    117     SkPaint paint;
    118     // we don't care about the mode, so try to use the existing one
    119     SkShader::TileMode mode = m_gradient ? m_gradient->m_tileMode :
    120                                             SkShader::kClamp_TileMode;
    121 
    122     paint.setAntiAlias(true);
    123     paint.setShader(this->getShader(mode));
    124     android_gc2canvas(context)->drawRect(rect, paint);
    125 }
    126 
    127 
    128 } //namespace
    129