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