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 "SkTypeface.h"
11
12/* This test tries to define the effect of using hairline strokes on text.
13 * Provides non-hairline images for reference and consistency checks.
14 * glyph_pos_(h/n)_(s/f/b)
15 *   -> test hairline/non-hairline stroke/fill/stroke+fill.
16 */
17static const SkScalar kTextHeight = 14.0f;
18static const char kText[] = "Proportional Hamburgefons #% fi";
19
20namespace skiagm {
21
22class GlyphPosGM : public GM {
23public:
24    GlyphPosGM(SkScalar strokeWidth, SkPaint::Style strokeStyle)
25        : fStrokeWidth(strokeWidth)
26        , fStrokeStyle(strokeStyle) {
27        }
28
29protected:
30    virtual uint32_t onGetFlags() const SK_OVERRIDE {
31        return kSkipTiled_Flag;
32    }
33
34    virtual SkString onShortName() SK_OVERRIDE {
35        SkString str("glyph_pos");
36        if (fStrokeWidth == 0.0f) {
37            str.append("_h"); // h == Hairline.
38        } else {
39            str.append("_n"); // n == Normal.
40        }
41        if (fStrokeStyle == SkPaint::kStroke_Style) {
42            str.append("_s");
43        } else if (fStrokeStyle == SkPaint::kFill_Style) {
44            str.append("_f");
45        } else {
46            str.append("_b"); // b == Both.
47        }
48        return str;
49    }
50
51    virtual SkISize onISize() { return SkISize::Make(800, 600); }
52
53    virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
54        if (!fProp) {
55            fProp.reset(sk_tool_utils::create_portable_typeface("Helvetica", SkTypeface::kNormal));
56        }
57
58        // There's a black pixel at 40, 40 for reference.
59        canvas->drawPoint(40.0f, 40.0f, SK_ColorBLACK);
60
61        // Two reference images.
62        canvas->translate(50.0f, 50.0f);
63        drawTestCase(canvas, 1.0f);
64
65        canvas->translate(0.0f, 50.0f);
66        drawTestCase(canvas, 3.0f);
67
68        // Uniform scaling test.
69        canvas->translate(0.0f, 100.0f);
70        canvas->save();
71        canvas->scale(3.0f, 3.0f);
72        drawTestCase(canvas, 1.0f);
73        canvas->restore();
74
75        // Non-uniform scaling test.
76        canvas->translate(0.0f, 100.0f);
77        canvas->save();
78        canvas->scale(3.0f, 6.0f);
79        drawTestCase(canvas, 1.0f);
80        canvas->restore();
81
82        // Skew test.
83        canvas->translate(0.0f, 80.0f);
84        canvas->save();
85        canvas->scale(3.0f, 3.0f);
86        SkMatrix skew;
87        skew.setIdentity();
88        skew.setSkewX(SkScalarDiv(8.0f,
89                                  25.0f));
90        skew.setSkewY(SkScalarDiv(2.0f,
91                                  25.0f));
92        canvas->concat(skew);
93        drawTestCase(canvas, 1.0f);
94        canvas->restore();
95
96        // Perspective test.
97        canvas->translate(0.0f, 80.0f);
98        canvas->save();
99        SkMatrix perspective;
100        perspective.setIdentity();
101        perspective.setPerspX(-SkScalarDiv(SK_Scalar1, 340.0f));
102        perspective.setSkewX(SkScalarDiv(8.0f,
103                                         25.0f));
104        perspective.setSkewY(SkScalarDiv(2.0f,
105                                         25.0f));
106
107
108        canvas->concat(perspective);
109        drawTestCase(canvas, 1.0f);
110        canvas->restore();
111    }
112
113    void drawTestCase(SkCanvas* canvas, SkScalar textScale) {
114        SkPaint paint;
115        paint.setColor(SK_ColorBLACK);
116        paint.setAntiAlias(true);
117        paint.setTextSize(kTextHeight * textScale);
118        paint.setTypeface(fProp);
119        paint.setDevKernText(true);
120        paint.setStrokeWidth(fStrokeWidth);
121        paint.setStyle(fStrokeStyle);
122
123        // This demonstrates that we can not measure the text if there's a device transform. The
124        // canvas total matrix will end up being a device transform.
125        bool drawRef = !(canvas->getTotalMatrix().getType() &
126                         ~(SkMatrix::kIdentity_Mask | SkMatrix::kTranslate_Mask));
127
128        SkRect bounds;
129        if (drawRef) {
130            SkScalar advance = paint.measureText(kText, sizeof(kText) - 1, &bounds);
131
132            paint.setStrokeWidth(0.0f);
133            paint.setStyle(SkPaint::kStroke_Style);
134
135            // Green box is the measured text bounds.
136            paint.setColor(SK_ColorGREEN);
137            canvas->drawRect(bounds, paint);
138
139            // Red line is the measured advance from the 0,0 of the text position.
140            paint.setColor(SK_ColorRED);
141            canvas->drawLine(0.0f, 0.0f, advance, 0.0f, paint);
142        }
143
144        // Black text is the testcase, eg. the text.
145        paint.setColor(SK_ColorBLACK);
146        paint.setStrokeWidth(fStrokeWidth);
147        paint.setStyle(fStrokeStyle);
148        canvas->drawText(kText, sizeof(kText) - 1, 0.0f, 0.0f, paint);
149
150        if (drawRef) {
151            SkScalar widths[sizeof(kText) - 1];
152            paint.getTextWidths(kText, sizeof(kText) - 1, widths, NULL);
153
154            paint.setStrokeWidth(0.0f);
155            paint.setStyle(SkPaint::kStroke_Style);
156
157            // Magenta lines are the positions for the characters.
158            paint.setColor(SK_ColorMAGENTA);
159            SkScalar w = bounds.x();
160            for (size_t i = 0; i < sizeof(kText) - 1; ++i) {
161                canvas->drawLine(w, 0.0f, w, 5.0f, paint);
162                w += widths[i];
163            }
164        }
165    }
166
167private:
168    SkAutoTUnref<SkTypeface> fProp;
169    SkScalar fStrokeWidth;
170    SkPaint::Style fStrokeStyle;
171
172    typedef GM INHERITED;
173};
174
175//////////////////////////////////////////////////////////////////////////////
176
177static GM* GlyphPosHairlineStrokeAndFillFactory(void*) {
178    return new GlyphPosGM(0.0f, SkPaint::kStrokeAndFill_Style);
179}
180static GM* GlyphPosStrokeAndFillFactory(void*) {
181    return new GlyphPosGM(1.2f, SkPaint::kStrokeAndFill_Style);
182}
183static GM* GlyphPosHairlineStrokeFactory(void*) {
184    return new GlyphPosGM(0.0f, SkPaint::kStroke_Style);
185}
186static GM* GlyphPosStrokeFactory(void*) {
187    return new GlyphPosGM(1.2f, SkPaint::kStroke_Style);
188}
189static GM* GlyphPosHairlineFillFactory(void*) {
190    return new GlyphPosGM(0.0f, SkPaint::kFill_Style);
191}
192static GM* GlyphPosFillFactory(void*) {
193    return new GlyphPosGM(1.2f, SkPaint::kFill_Style);
194}
195
196static GMRegistry reg1(GlyphPosHairlineStrokeAndFillFactory);
197static GMRegistry reg2(GlyphPosStrokeAndFillFactory);
198static GMRegistry reg3(GlyphPosHairlineStrokeFactory);
199static GMRegistry reg4(GlyphPosStrokeFactory);
200static GMRegistry reg5(GlyphPosHairlineFillFactory);
201static GMRegistry reg6(GlyphPosFillFactory);
202
203
204}
205