| /* |
| * Copyright 2011 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "include/core/SkCanvas.h" |
| #include "include/core/SkFont.h" |
| #include "include/core/SkString.h" |
| #include "include/effects/SkGradientShader.h" |
| #include "tools/fonts/FontToolUtils.h" |
| #include "tools/viewer/Slide.h" |
| |
| static void draw_gradient2(SkCanvas* canvas, const SkRect& rect, SkScalar delta) { |
| SkColor colors[] = { SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorMAGENTA }; |
| SkScalar pos[] = { 0, 0.25f, 0.75f, SK_Scalar1 }; |
| |
| SkScalar l = rect.fLeft; |
| SkScalar t = rect.fTop; |
| SkScalar w = rect.width(); |
| SkScalar h = rect.height(); |
| |
| SkASSERT(0 == SkScalarMod(w, SK_Scalar1 * 5)); |
| |
| SkPoint c0 = { l + 2 * w / 5 + delta, t + h / 2 }; |
| SkPoint c1 = { l + 3 * w / 5, t + h / 2 }; |
| SkScalar r0 = w / 5; |
| SkScalar r1 = 2 * w / 5; |
| SkPaint paint; |
| paint.setShader(SkGradientShader::MakeTwoPointConical(c0, r0, c1, r1, colors, |
| pos, std::size(pos), |
| SkTileMode::kClamp)); |
| canvas->drawRect(rect, paint); |
| } |
| |
| |
| class DegenerateTwoPtRadialsSlide : public Slide { |
| public: |
| DegenerateTwoPtRadialsSlide() { fName = "DegenerateTwoPtRadials"; } |
| |
| void draw(SkCanvas* canvas) override { |
| canvas->clear(0xFFDDDDDD); |
| SkScalar delta = fTime / 15.f; |
| int intPart = SkScalarFloorToInt(delta); |
| delta = delta - SK_Scalar1 * intPart; |
| if (intPart % 2) { |
| delta = SK_Scalar1 - delta; |
| } |
| delta -= SK_ScalarHalf; |
| static const int DELTA_SCALE = 500; |
| delta /= DELTA_SCALE; |
| |
| SkScalar w = SK_Scalar1 * 500; |
| SkScalar h = SK_Scalar1 * 500; |
| SkScalar l = SK_Scalar1 * 100; |
| SkScalar t = SK_Scalar1 * 100; |
| draw_gradient2(canvas, SkRect::MakeXYWH(l, t, w, h), delta); |
| SkString txt; |
| txt.appendf("gap at \"tangent\" pt = %f", delta); |
| canvas->drawString(txt, |
| l + w / 2 + w * DELTA_SCALE * delta, |
| t + h + SK_Scalar1 * 10, |
| ToolUtils::DefaultFont(), |
| SkPaint()); |
| } |
| |
| bool animate(double nanos) override { |
| fTime = SkDoubleToScalar(1e-9 * nanos / 15); |
| return true; |
| } |
| |
| private: |
| SkScalar fTime; |
| }; |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| DEF_SLIDE( return new DegenerateTwoPtRadialsSlide(); ) |