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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 
      8 
      9 /* Tests text rendering with LCD and subpixel rendering turned on and off.
     10  */
     11 
     12 #include "gm.h"
     13 #include "sk_tool_utils.h"
     14 #include "SkCanvas.h"
     15 #include "SkPicture.h"
     16 #include "SkPictureImageFilter.h"
     17 #include "SkPictureRecorder.h"
     18 #include "SkSurface.h"
     19 
     20 
     21 class LcdTextGM : public skiagm::GM {
     22 public:
     23     LcdTextGM() {
     24         const int pointSize = 36;
     25         textHeight = SkIntToScalar(pointSize);
     26     }
     27 
     28 protected:
     29 
     30     SkString onShortName() {
     31         SkString name("lcdtext");
     32         name.append(sk_tool_utils::platform_font_manager());
     33         return name;
     34     }
     35 
     36     SkISize onISize() { return SkISize::Make(640, 480); }
     37 
     38     virtual void onDraw(SkCanvas* canvas) {
     39 
     40         y = textHeight;
     41         drawText(canvas, SkString("TEXT: SubpixelTrue LCDRenderTrue"),
     42                  true,  true);
     43         drawText(canvas, SkString("TEXT: SubpixelTrue LCDRenderFalse"),
     44                  true,  false);
     45         drawText(canvas, SkString("TEXT: SubpixelFalse LCDRenderTrue"),
     46                  false, true);
     47         drawText(canvas, SkString("TEXT: SubpixelFalse LCDRenderFalse"),
     48                  false, false);
     49     }
     50 
     51     void drawText(SkCanvas* canvas, const SkString& string,
     52                   bool subpixelTextEnabled, bool lcdRenderTextEnabled) {
     53         SkPaint paint;
     54         paint.setColor(SK_ColorBLACK);
     55         paint.setDither(true);
     56         paint.setAntiAlias(true);
     57         paint.setSubpixelText(subpixelTextEnabled);
     58         paint.setLCDRenderText(lcdRenderTextEnabled);
     59         paint.setTextSize(textHeight);
     60 
     61         canvas->drawString(string, 0, y, paint);
     62         y += textHeight;
     63     }
     64 
     65 private:
     66     typedef skiagm::GM INHERITED;
     67     SkScalar y, textHeight;
     68 };
     69 
     70 /*
     71  *  Skia will automatically disable LCD requests if the total size exceeds some limit
     72  *  (hard coded in this test for now, as it is now avaiable as an API)
     73  *
     74  *  Test this both by changing "textsize" and by changing the computed size (textsize * CTM)
     75  */
     76 class LcdTextSizeGM : public skiagm::GM {
     77     enum {
     78         kLCDTextSizeLimit = 48
     79     };
     80 
     81     static void ScaleAbout(SkCanvas* canvas, SkScalar sx, SkScalar sy, SkScalar px, SkScalar py) {
     82         SkMatrix m;
     83         m.setScale(sx, sy, px, py);
     84         canvas->concat(m);
     85     }
     86 
     87 public:
     88     LcdTextSizeGM() {}
     89 
     90 protected:
     91     SkString onShortName() {
     92         return SkString("lcdtextsize");
     93     }
     94 
     95     SkISize onISize() { return SkISize::Make(320, 120); }
     96 
     97     virtual void onDraw(SkCanvas* canvas) {
     98         const char* lcd_text = "LCD";
     99         const char* gray_text = "GRAY";
    100 
    101         SkPaint paint;
    102         paint.setAntiAlias(true);
    103         paint.setLCDRenderText(true);
    104 
    105         const struct {
    106             SkPoint     fLoc;
    107             SkScalar    fTextSize;
    108             SkScalar    fScale;
    109             const char* fText;
    110         } rec[] = {
    111             { {  10,  50 }, kLCDTextSizeLimit - 1,     1,  lcd_text },
    112             { { 160,  50 }, kLCDTextSizeLimit + 1,     1,  gray_text },
    113             { {  10, 100 }, kLCDTextSizeLimit / 2, 1.99f,  lcd_text },
    114             { { 160, 100 }, kLCDTextSizeLimit / 2, 2.01f,  gray_text },
    115         };
    116 
    117         for (size_t i = 0; i < SK_ARRAY_COUNT(rec); ++i) {
    118             const SkPoint loc = rec[i].fLoc;
    119             SkAutoCanvasRestore acr(canvas, true);
    120 
    121             paint.setTextSize(rec[i].fTextSize);
    122             ScaleAbout(canvas, rec[i].fScale, rec[i].fScale, loc.x(), loc.y());
    123             canvas->drawString(rec[i].fText, loc.x(), loc.y(), paint);
    124         }
    125     }
    126 
    127 private:
    128     typedef skiagm::GM INHERITED;
    129 };
    130 DEF_GM( return new LcdTextGM; )
    131 DEF_GM( return new LcdTextSizeGM; )
    132 
    133 ///////////////////////////////////////////////////////////////////////////////////////////////////
    134 
    135 DEF_SIMPLE_GM(savelayer_lcdtext, canvas, 620, 260) {
    136     SkPaint paint;
    137     paint.setAntiAlias(true);
    138     paint.setLCDRenderText(true);
    139     paint.setTextSize(20);
    140 
    141     canvas->drawString("Hamburgefons", 30, 30, paint);
    142 
    143     const bool gPreserveLCDText[] = { false, true };
    144 
    145     canvas->translate(0, 20);
    146     for (auto preserve : gPreserveLCDText) {
    147         preserve ? canvas->saveLayerPreserveLCDTextRequests(nullptr, nullptr)
    148                  : canvas->saveLayer(nullptr, nullptr);
    149         if (preserve && !canvas->imageInfo().colorSpace()) {
    150             SkPaint noLCD = paint;
    151             noLCD.setLCDRenderText(false);
    152             canvas->drawString("LCD not supported", 30, 60, noLCD);
    153         } else {
    154             canvas->drawString("Hamburgefons", 30, 60, paint);
    155         }
    156 
    157         SkPaint p;
    158         p.setColor(0xFFCCCCCC);
    159         canvas->drawRect(SkRect::MakeLTRB(25, 70, 200, 100), p);
    160         canvas->drawString("Hamburgefons", 30, 90, paint);
    161 
    162         canvas->restore();
    163         canvas->translate(0, 80);
    164     }
    165 }
    166