gm/glyph_pos_align.cpp

   1 /*
   2  * Copyright 2014 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 #include "gm.h"
   9 #include "SkCanvas.h"
  10 #include "SkGradientShader.h"
  11
  12 /**
  13  * This test exercises drawPosTextH and drawPosText with every text align.
  14  */
  15 constexpr int kWidth = 480;
  16 constexpr int kHeight = 600;
  17 constexpr SkScalar kTextHeight = 64.0f;
  18 constexpr int kMaxStringLength = 12;
  19
  20 static void drawTestCase(SkCanvas*, const char*, SkScalar, const SkPaint&);
  21
  22 DEF_SIMPLE_GM_BG(glyph_pos_align, canvas, kWidth, kHeight, SK_ColorBLACK) {
  23         SkPaint paint;
  24         paint.setTextSize(kTextHeight);
  25         paint.setFakeBoldText(true);
  26         const SkColor colors[] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE };
  27         const SkPoint pts[] = {{0, 0}, {kWidth, kHeight}};
  28         paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
  29                                                      SkShader::kMirror_TileMode));
  30         paint.setTextAlign(SkPaint::kRight_Align);
  31         drawTestCase(canvas, "Right Align", kTextHeight, paint);
  32
  33         paint.setTextAlign(SkPaint::kCenter_Align);
  34         drawTestCase(canvas, "Center Align", 4 * kTextHeight, paint);
  35
  36         paint.setTextAlign(SkPaint::kLeft_Align);
  37         drawTestCase(canvas, "Left Align", 7 * kTextHeight, paint);
  38 }
  39
  40 void drawTestCase(SkCanvas* canvas, const char* text, SkScalar y, const SkPaint& paint) {
  41         SkScalar widths[kMaxStringLength];
  42         SkScalar posX[kMaxStringLength];
  43         SkPoint pos[kMaxStringLength];
  44         int length = SkToInt(strlen(text));
  45         SkASSERT(length <= kMaxStringLength);
  46
  47         paint.getTextWidths(text, length, widths);
  48
  49         float originX;
  50         switch (paint.getTextAlign()) {
  51             case SkPaint::kRight_Align: originX = 1; break;
  52             case SkPaint::kCenter_Align: originX = 0.5f; break;
  53             case SkPaint::kLeft_Align: originX = 0; break;
  54             default: SkFAIL("Invalid paint origin"); return;
  55         }
  56
  57         float x = kTextHeight;
  58         for (int i = 0; i < length; ++i) {
  59             posX[i] = x + originX * widths[i];
  60             pos[i].set(posX[i], i ? pos[i - 1].y() + 3 : y + kTextHeight);
  61             x += widths[i];
  62         }
  63
  64         canvas->drawPosTextH(text, length, posX, y, paint);
  65         canvas->drawPosText(text, length, pos, paint);
  66 }