xref: /third_party/skia/tests/DrawTextTest.cpp (revision cb93a386)
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#include "include/core/SkBitmap.h"
9#include "include/core/SkCanvas.h"
10#include "include/core/SkColor.h"
11#include "include/core/SkFont.h"
12#include "include/core/SkMatrix.h"
13#include "include/core/SkPaint.h"
14#include "include/core/SkPathEffect.h"
15#include "include/core/SkPoint.h"
16#include "include/core/SkRect.h"
17#include "include/core/SkRefCnt.h"
18#include "include/core/SkScalar.h"
19#include "include/core/SkSurface.h"
20#include "include/core/SkTextBlob.h"
21#include "include/core/SkTypeface.h"
22#include "include/core/SkTypes.h"
23#include "include/effects/SkDashPathEffect.h"
24#include "tests/Test.h"
25
26#include <cmath>
27
28static const SkColor bgColor = SK_ColorWHITE;
29
30static void create(SkBitmap* bm, SkIRect bound) {
31    bm->allocN32Pixels(bound.width(), bound.height());
32}
33
34/** Assumes that the ref draw was completely inside ref canvas --
35    implies that everything outside is "bgColor".
36    Checks that all overlap is the same and that all non-overlap on the
37    ref is "bgColor".
38 */
39static bool compare(const SkBitmap& ref, const SkIRect& iref,
40                    const SkBitmap& test, const SkIRect& itest)
41{
42    const int xOff = itest.fLeft - iref.fLeft;
43    const int yOff = itest.fTop - iref.fTop;
44
45    for (int y = 0; y < test.height(); ++y) {
46        for (int x = 0; x < test.width(); ++x) {
47            SkColor testColor = test.getColor(x, y);
48            int refX = x + xOff;
49            int refY = y + yOff;
50            SkColor refColor;
51            if (refX >= 0 && refX < ref.width() &&
52                refY >= 0 && refY < ref.height())
53            {
54                refColor = ref.getColor(refX, refY);
55            } else {
56                refColor = bgColor;
57            }
58            if (refColor != testColor) {
59                return false;
60            }
61        }
62    }
63    return true;
64}
65
66/** Test that drawing glyphs with empty paths is different from drawing glyphs without paths. */
67DEF_TEST(DrawText_dashout, reporter) {
68    SkIRect size = SkIRect::MakeWH(64, 64);
69
70    SkBitmap drawTextBitmap;
71    create(&drawTextBitmap, size);
72    SkCanvas drawTextCanvas(drawTextBitmap);
73
74    SkBitmap drawDashedTextBitmap;
75    create(&drawDashedTextBitmap, size);
76    SkCanvas drawDashedTextCanvas(drawDashedTextBitmap);
77
78    SkBitmap emptyBitmap;
79    create(&emptyBitmap, size);
80    SkCanvas emptyCanvas(emptyBitmap);
81
82    SkPoint point = SkPoint::Make(25.0f, 25.0f);
83    SkFont font(nullptr, 20);
84    font.setEdging(SkFont::Edging::kSubpixelAntiAlias);
85    font.setSubpixel(true);
86
87    SkPaint paint;
88    paint.setColor(SK_ColorGRAY);
89    paint.setStyle(SkPaint::kStroke_Style);
90
91    // Draw a stroked "A" without a dash which will draw something.
92    drawTextCanvas.drawColor(SK_ColorWHITE);
93    drawTextCanvas.drawString("A", point.fX, point.fY, font, paint);
94
95    // Draw an "A" but with a dash which will never draw anything.
96    paint.setStrokeWidth(2);
97    constexpr SkScalar bigInterval = 10000;
98    static constexpr SkScalar intervals[] = { 1, bigInterval };
99    paint.setPathEffect(SkDashPathEffect::Make(intervals, SK_ARRAY_COUNT(intervals), 2));
100
101    drawDashedTextCanvas.drawColor(SK_ColorWHITE);
102    drawDashedTextCanvas.drawString("A", point.fX, point.fY, font, paint);
103
104    // Draw nothing.
105    emptyCanvas.drawColor(SK_ColorWHITE);
106
107    REPORTER_ASSERT(reporter, !compare(drawTextBitmap, size, emptyBitmap, size));
108    REPORTER_ASSERT(reporter, compare(drawDashedTextBitmap, size, emptyBitmap, size));
109}
110
111// Test drawing text at some unusual coordinates.
112// We measure success by not crashing or asserting.
113DEF_TEST(DrawText_weirdCoordinates, r) {
114    auto surface = SkSurface::MakeRasterN32Premul(10,10);
115    auto canvas = surface->getCanvas();
116
117    SkScalar oddballs[] = { 0.0f, (float)INFINITY, (float)NAN, 34359738368.0f };
118
119    for (auto x : oddballs) {
120        canvas->drawString("a", +x, 0.0f, SkFont(), SkPaint());
121        canvas->drawString("a", -x, 0.0f, SkFont(), SkPaint());
122    }
123    for (auto y : oddballs) {
124        canvas->drawString("a", 0.0f, +y, SkFont(), SkPaint());
125        canvas->drawString("a", 0.0f, -y, SkFont(), SkPaint());
126    }
127}
128
129// Test drawing text with some unusual matricies.
130// We measure success by not crashing or asserting.
131DEF_TEST(DrawText_weirdMatricies, r) {
132    auto surface = SkSurface::MakeRasterN32Premul(100,100);
133    auto canvas = surface->getCanvas();
134
135    SkFont font;
136    font.setEdging(SkFont::Edging::kSubpixelAntiAlias);
137
138    struct {
139        SkScalar textSize;
140        SkScalar matrix[9];
141    } testCases[] = {
142        // 2x2 singular
143        {10, { 0,  0,  0,  0,  0,  0,  0,  0,  1}},
144        {10, { 0,  0,  0,  0,  1,  0,  0,  0,  1}},
145        {10, { 0,  0,  0,  1,  0,  0,  0,  0,  1}},
146        {10, { 0,  0,  0,  1,  1,  0,  0,  0,  1}},
147        {10, { 0,  1,  0,  0,  1,  0,  0,  0,  1}},
148        {10, { 1,  0,  0,  0,  0,  0,  0,  0,  1}},
149        {10, { 1,  0,  0,  1,  0,  0,  0,  0,  1}},
150        {10, { 1,  1,  0,  0,  0,  0,  0,  0,  1}},
151        {10, { 1,  1,  0,  1,  1,  0,  0,  0,  1}},
152        // See https://bugzilla.mozilla.org/show_bug.cgi?id=1305085 .
153        { 1, {10, 20,  0, 20, 40,  0,  0,  0,  1}},
154    };
155
156    for (const auto& testCase : testCases) {
157        font.setSize(testCase.textSize);
158        const SkScalar(&m)[9] = testCase.matrix;
159        SkMatrix mat;
160        mat.setAll(m[0], m[1], m[2], m[3], m[4], m[5], m[6], m[7], m[8]);
161        canvas->setMatrix(mat);
162        canvas->drawString("Hamburgefons", 10, 10, font, SkPaint());
163    }
164}
165
166// This produces no glyphs, and is to check that buffers from previous draws don't get
167// reused.
168DEF_TEST(DrawText_noglyphs, r) {
169    auto surface = SkSurface::MakeRasterN32Premul(100,100);
170    auto canvas = surface->getCanvas();
171    auto text = "Hamburgfons";
172    {
173        // scoped to ensure blob is deleted.
174        auto blob = SkTextBlob::MakeFromText(text, strlen(text), SkFont());
175        canvas->drawTextBlob(blob, 10, 10, SkPaint());
176    }
177    canvas->drawString(
178            "\x0d\xf3\xf2\xf2\xe9\x0d\x0d\x0d\x05\x0d\x0d\xe3\xe3\xe3\xe3\xe3\xe3\xe3\xe3\xe3",
179            10, 20, SkFont(), SkPaint());
180}
181