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