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- /*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- /*
- * This GM presents a variety of different gradients with different
- * tile modes. Each entry in the table is a rectangle with a linear
- * gradient that spans from its left edge to its right edge. The rows
- * in the table represent different color/position configurations,
- * while the columns in the table represent different tile modes. In
- * order to highlight the differences between tile modes, the gradient
- * starts and ends at 30 pixel inset from either side of the rectangle.
- *
- * | Clamp Repeat Mirror
- * _____________________________|___________________________________________
- * 2-color | rect00 rect01 rect02
- * 3-color even | rect10 rect11 rect12
- * 3-color texture | rect20 rect21 rect22
- * 5-color hard stop | rect30 rect31 rect32
- * 4-color hard stop centered | rect40 rect41 rect42
- * 3-color hard stop 001 | rect50 rect51 rect52
- * 3-color hard stop 011 | rect60 rect61 rect62
- * 4-color hard stop off-center | rect70 rect71 rect72
- *
- * The first three rows are cases covered by pre-hard-stop code; simple
- * 2-color gradients, 3-color gradients with the middle color centered,
- * and general gradients that are rendered from a texture atlas.
- *
- * The next four rows all deal with hard stop gradients. The fourth row
- * is a generic hard stop gradient, while the three subsequent rows deal
- * with special cases of hard stop gradients; centered hard stop gradients
- * (with t-values 0, 0.5, 0.5, 1), and two edge cases (with t-values
- * 0, 0, 1 and 0, 1, 1). The final row has a single off-center hard stop.
- */
- #include "gm/gm.h"
- #include "include/core/SkCanvas.h"
- #include "include/core/SkColor.h"
- #include "include/core/SkPaint.h"
- #include "include/core/SkPoint.h"
- #include "include/core/SkRect.h"
- #include "include/core/SkRefCnt.h"
- #include "include/core/SkScalar.h"
- #include "include/core/SkShader.h"
- #include "include/core/SkSize.h"
- #include "include/core/SkString.h"
- #include "include/core/SkTileMode.h"
- #include "include/effects/SkGradientShader.h"
- const int WIDTH = 500;
- const int HEIGHT = 500;
- const int NUM_ROWS = 8;
- const int NUM_COLS = 3;
- const int CELL_WIDTH = WIDTH / NUM_COLS;
- const int CELL_HEIGHT = HEIGHT / NUM_ROWS;
- const int PAD_WIDTH = 3;
- const int PAD_HEIGHT = 3;
- const int RECT_WIDTH = CELL_WIDTH - (2 * PAD_WIDTH);
- const int RECT_HEIGHT = CELL_HEIGHT - (2 * PAD_HEIGHT);
- static void shade_rect(SkCanvas* canvas, sk_sp<SkShader> shader, int cellRow, int cellCol) {
- SkPaint paint;
- paint.setShader(shader);
- SkRect rect = SkRect::MakeXYWH(SkIntToScalar(cellCol * CELL_WIDTH + PAD_WIDTH),
- SkIntToScalar(cellRow * CELL_HEIGHT + PAD_HEIGHT),
- SkIntToScalar(RECT_WIDTH),
- SkIntToScalar(RECT_HEIGHT));
- canvas->drawRect(rect, paint);
- }
- static void create_gradient_points(int cellRow, int cellCol, SkPoint points[2]) {
- const int X_OFFSET = 30;
- auto x0 = SkIntToScalar(cellCol * CELL_WIDTH + PAD_WIDTH + X_OFFSET);
- auto x1 = SkIntToScalar((cellCol+1) * CELL_WIDTH - PAD_WIDTH - X_OFFSET);
- auto y = SkIntToScalar(cellRow * CELL_HEIGHT + PAD_HEIGHT + RECT_HEIGHT/2);
- points[0] = SkPoint::Make(x0, y);
- points[1] = SkPoint::Make(x1, y);
- }
- class HardstopGradientShaderGM : public skiagm::GM {
- public:
- HardstopGradientShaderGM() {
- }
- protected:
- SkString onShortName() override {
- return SkString("hardstop_gradients");
- }
- SkISize onISize() override {
- return SkISize::Make(512, 512);
- }
- void onDraw(SkCanvas* canvas) override {
- SkPoint points[2];
- SkColor colors[] = {
- SK_ColorRED,
- SK_ColorGREEN,
- SK_ColorBLUE,
- SK_ColorYELLOW,
- SK_ColorMAGENTA,
- };
- SkScalar row3[] = {0.00f, 0.25f, 1.00f};
- SkScalar row4[] = {0.00f, 0.25f, 0.50f, 0.50f, 1.00f};
- SkScalar row5[] = {0.00f, 0.50f, 0.50f, 1.00f};
- SkScalar row6[] = {0.00f, 0.00f, 1.00f};
- SkScalar row7[] = {0.00f, 1.00f, 1.00f};
- SkScalar row8[] = {0.00f, 0.30f, 0.30f, 1.00f};
- SkScalar* positions[NUM_ROWS] = {
- nullptr,
- nullptr,
- row3,
- row4,
- row5,
- row6,
- row7,
- row8,
- };
- int numGradientColors[NUM_ROWS] = {
- 2,
- 3,
- 3,
- 5,
- 4,
- 3,
- 3,
- 4,
- };
- SkTileMode tilemodes[NUM_COLS] = {
- SkTileMode::kClamp,
- SkTileMode::kRepeat,
- SkTileMode::kMirror,
- };
- for (int cellRow = 0; cellRow < NUM_ROWS; cellRow++) {
- for (int cellCol = 0; cellCol < NUM_COLS; cellCol++) {
- create_gradient_points(cellRow, cellCol, points);
- auto shader = SkGradientShader::MakeLinear(
- points,
- colors,
- positions[cellRow],
- numGradientColors[cellRow],
- tilemodes[cellCol],
- 0,
- nullptr);
- shade_rect(canvas, shader, cellRow, cellCol);
- }
- }
- }
- private:
- typedef skiagm::GM INHERITED;
- };
- DEF_GM(return new HardstopGradientShaderGM;)
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