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      1 
      2 /*
      3  * Copyright 2011 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 #include "sk_tool_utils.h"
      9 #include "SampleCode.h"
     10 #include "SkView.h"
     11 #include "SkCanvas.h"
     12 #include "SkColorFilter.h"
     13 #include "SkDevice.h"
     14 #include "SkPaint.h"
     15 #include "SkShader.h"
     16 
     17 static int inflate5To8(int x) {
     18     return (x << 3) | (x >> 2);
     19 }
     20 
     21 static int trunc5(int x) {
     22     return x >> 3;
     23 }
     24 
     25 #define SK_R16_BITS 5
     26 
     27 #ifdef SK_DEBUG
     28 static int round5_slow(int x) {
     29     int orig = x & 7;
     30     int fake = x >> 5;
     31     int trunc = x >> 3;
     32 
     33     int diff = fake - orig;
     34 
     35     int bias = 0;
     36     if (diff > 4) {
     37         bias = -1;
     38     } else if (diff < -4) {
     39         bias = 1;
     40     }
     41     return trunc + bias;
     42 }
     43 #endif
     44 
     45 static int round5_fast(int x) {
     46     int result = x + 3 - (x >> 5) + (x >> 7);
     47     result >>= 3;
     48 #ifdef SK_DEBUG
     49     {
     50         int r2 = round5_slow(x);
     51         SkASSERT(r2 == result);
     52     }
     53 #endif
     54     return result;
     55 }
     56 
     57 static void test_5bits() {
     58     int e0 = 0;
     59     int e1 = 0;
     60     int e2 = 0;
     61     int ae0 = 0;
     62     int ae1 = 0;
     63     int ae2 = 0;
     64     for (int i = 0; i < 256; i++) {
     65         int t0 = trunc5(i);
     66         int t1 = round5_fast(i);
     67         int t2 = trunc5(i);
     68         int v0 = inflate5To8(t0);
     69         int v1 = inflate5To8(t1);
     70         int v2 = inflate5To8(t2);
     71         int err0 = i - v0;
     72         int err1 = i - v1;
     73         int err2 = i - v2;
     74         SkDebugf("--- %3d : trunc=%3d (%2d) round:%3d (%2d) \n"/*new:%d (%2d)\n"*/, i,
     75                  v0, err0, v1, err1, v2, err2);
     76 
     77 
     78         e0 += err0;
     79         e1 += err1;
     80         e2 += err2;
     81         ae0 += SkAbs32(err0);
     82         ae1 += SkAbs32(err1);
     83         ae2 += SkAbs32(err2);
     84     }
     85     SkDebugf("--- trunc: %d %d  round: %d %d new: %d %d\n", e0, ae0, e1, ae1, e2, ae2);
     86 }
     87 
     88 static SkBitmap createBitmap(int n) {
     89     SkBitmap bitmap;
     90     bitmap.allocN32Pixels(n, n);
     91     bitmap.eraseColor(SK_ColorTRANSPARENT);
     92 
     93     SkCanvas canvas(bitmap);
     94     SkRect r;
     95     r.set(0, 0, SkIntToScalar(n), SkIntToScalar(n));
     96     r.inset(SK_Scalar1, SK_Scalar1);
     97 
     98     SkPaint paint;
     99     paint.setAntiAlias(true);
    100 
    101     paint.setColor(SK_ColorRED);
    102     canvas.drawOval(r, paint);
    103 
    104     r.inset(SK_Scalar1*n/4, SK_Scalar1*n/4);
    105     paint.setXfermodeMode(SkXfermode::kSrc_Mode);
    106     paint.setColor(0x800000FF);
    107     canvas.drawOval(r, paint);
    108 
    109     return bitmap;
    110 }
    111 
    112 class ColorFilterView : public SampleView {
    113     SkBitmap fBitmap;
    114     SkShader* fShader;
    115     enum {
    116         N = 64
    117     };
    118 public:
    119     ColorFilterView() {
    120         fBitmap = createBitmap(N);
    121         fShader = sk_tool_utils::create_checkerboard_shader(
    122                 0xFFCCCCCC, 0xFFFFFFFF, 12);
    123 
    124         if (false) { // avoid bit rot, suppress warning
    125             test_5bits();
    126         }
    127     }
    128 
    129     virtual ~ColorFilterView() {
    130         fShader->unref();
    131     }
    132 
    133 protected:
    134     // overrides from SkEventSink
    135     virtual bool onQuery(SkEvent* evt) {
    136         if (SampleCode::TitleQ(*evt)) {
    137             SampleCode::TitleR(evt, "ColorFilter");
    138             return true;
    139         }
    140         return this->INHERITED::onQuery(evt);
    141     }
    142 
    143     virtual void onDrawBackground(SkCanvas* canvas) {
    144         SkPaint paint;
    145         paint.setShader(fShader);
    146         canvas->drawPaint(paint);
    147     }
    148 
    149     virtual void onDrawContent(SkCanvas* canvas) {
    150         if (false) {
    151             SkPaint p;
    152             p.setAntiAlias(true);
    153             SkRect r = { 20.4f, 10, 20.6f, 20 };
    154             canvas->drawRect(r, p);
    155             r.set(30.9f, 10, 31.1f, 20);
    156             canvas->drawRect(r, p);
    157             return;
    158         }
    159 
    160         static const SkXfermode::Mode gModes[] = {
    161             SkXfermode::kClear_Mode,
    162             SkXfermode::kSrc_Mode,
    163             SkXfermode::kDst_Mode,
    164             SkXfermode::kSrcOver_Mode,
    165             SkXfermode::kDstOver_Mode,
    166             SkXfermode::kSrcIn_Mode,
    167             SkXfermode::kDstIn_Mode,
    168             SkXfermode::kSrcOut_Mode,
    169             SkXfermode::kDstOut_Mode,
    170             SkXfermode::kSrcATop_Mode,
    171             SkXfermode::kDstATop_Mode,
    172             SkXfermode::kXor_Mode,
    173             SkXfermode::kPlus_Mode,
    174             SkXfermode::kModulate_Mode,
    175         };
    176 
    177         static const SkColor gColors[] = {
    178             0xFF000000,
    179             0x80000000,
    180             0xFF00FF00,
    181             0x8000FF00,
    182             0x00000000,
    183         };
    184 
    185         float scale = 1.5f;
    186         SkPaint paint;
    187         canvas->translate(N / 8, N / 8);
    188 
    189         for (size_t y = 0; y < SK_ARRAY_COUNT(gColors); y++) {
    190             for (size_t x = 0; x < SK_ARRAY_COUNT(gModes); x++) {
    191                 SkColorFilter* cf = SkColorFilter::CreateModeFilter(gColors[y], gModes[x]);
    192                 SkSafeUnref(paint.setColorFilter(cf));
    193                 canvas->drawBitmap(fBitmap, x * N * 1.25f, y * N * scale, &paint);
    194             }
    195         }
    196 
    197     }
    198 
    199 private:
    200     typedef SampleView INHERITED;
    201 };
    202 
    203 //////////////////////////////////////////////////////////////////////////////
    204 
    205 static SkView* MyFactory() { return new ColorFilterView; }
    206 static SkViewRegister reg(MyFactory);
    207