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/*
* Copyright 2018 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm/gm.h"
#include "include/core/SkFont.h"
#include "include/effects/SkGradientShader.h"
// NOTE: The positions define hardstops for the red and green borders. For the repeating degenerate
// gradients, that means the red and green are never visible, so the average color used should only
// be based off of the white, blue, black blend.
static const SkColor COLORS[] = { SK_ColorRED, SK_ColorWHITE, SK_ColorBLUE,
SK_ColorBLACK, SK_ColorGREEN };
static const SkScalar POS[] = { 0.0, 0.0, 0.5, 1.0, 1.0 };
static const int COLOR_CT = SK_ARRAY_COUNT(COLORS);
static const SkTileMode TILE_MODES[] = { SkTileMode::kDecal,
SkTileMode::kRepeat,
SkTileMode::kMirror,
SkTileMode::kClamp };
static const char* TILE_NAMES[] = { "decal", "repeat", "mirror", "clamp" };
static const int TILE_MODE_CT = SK_ARRAY_COUNT(TILE_MODES);
static constexpr int TILE_SIZE = 100;
static constexpr int TILE_GAP = 10;
static const SkPoint CENTER = SkPoint::Make(TILE_SIZE / 2, TILE_SIZE / 2);
typedef sk_sp<SkShader> (*GradientFactory)(SkTileMode tm);
static void draw_tile_header(SkCanvas* canvas) {
canvas->save();
for (int i = 0; i < TILE_MODE_CT; ++i) {
canvas->drawString(TILE_NAMES[i], 0, 0, SkFont(), SkPaint());
canvas->translate(TILE_SIZE + TILE_GAP, 0);
}
canvas->restore();
// Now adjust to start at rows below the header
canvas->translate(0, 2 * TILE_GAP);
}
static void draw_row(SkCanvas* canvas, const char* desc, GradientFactory factory) {
canvas->save();
SkPaint text;
text.setAntiAlias(true);
canvas->translate(0, TILE_GAP);
canvas->drawString(desc, 0, 0, SkFont(), text);
canvas->translate(0, TILE_GAP);
SkPaint paint;
paint.setColor(SK_ColorBLACK);
paint.setStyle(SkPaint::kStrokeAndFill_Style);
paint.setStrokeWidth(2.0f);
for (int i = 0; i < TILE_MODE_CT; ++i) {
paint.setShader(factory(TILE_MODES[i]));
canvas->drawRect(SkRect::MakeWH(TILE_SIZE, TILE_SIZE), paint);
canvas->translate(TILE_SIZE + TILE_GAP, 0);
}
canvas->restore();
// Now adjust to start the next row below this one (1 gap for text and 2 gap for margin)
canvas->translate(0, 3 * TILE_GAP + TILE_SIZE);
}
static sk_sp<SkShader> make_linear(SkTileMode mode) {
// Same position
SkPoint pts[2] = {CENTER, CENTER};
return SkGradientShader::MakeLinear(pts, COLORS, POS, COLOR_CT, mode);
}
static sk_sp<SkShader> make_radial(SkTileMode mode) {
// Radius = 0
return SkGradientShader::MakeRadial(CENTER, 0.0, COLORS, POS, COLOR_CT, mode);
}
static sk_sp<SkShader> make_sweep(SkTileMode mode) {
// Start and end angles at 45
static constexpr SkScalar SWEEP_ANG = 45.0;
return SkGradientShader::MakeSweep(CENTER.fX, CENTER.fY, COLORS, POS, COLOR_CT, mode,
SWEEP_ANG, SWEEP_ANG, 0, nullptr);
}
static sk_sp<SkShader> make_sweep_zero_ang(SkTileMode mode) {
// Start and end angles at 0
return SkGradientShader::MakeSweep(CENTER.fX, CENTER.fY, COLORS, POS, COLOR_CT, mode,
0.0, 0.0, 0, nullptr);
}
static sk_sp<SkShader> make_2pt_conic(SkTileMode mode) {
// Start and end radius = TILE_SIZE, same position
return SkGradientShader::MakeTwoPointConical(CENTER, TILE_SIZE / 2, CENTER, TILE_SIZE / 2,
COLORS, POS, COLOR_CT, mode);
}
static sk_sp<SkShader> make_2pt_conic_zero_rad(SkTileMode mode) {
// Start and end radius = 0, same position
return SkGradientShader::MakeTwoPointConical(CENTER, 0.0, CENTER, 0.0, COLORS, POS,
COLOR_CT, mode);
}
class DegenerateGradientGM : public skiagm::GM {
public:
DegenerateGradientGM() {
}
protected:
SkString onShortName() override {
return SkString("degenerate_gradients");
}
SkISize onISize() override {
return SkISize::Make(800, 800);
}
void onDraw(SkCanvas* canvas) override {
canvas->translate(3 * TILE_GAP, 3 * TILE_GAP);
draw_tile_header(canvas);
draw_row(canvas, "linear: empty, blue, blue, green", make_linear);
draw_row(canvas, "radial: empty, blue, blue, green", make_radial);
draw_row(canvas, "sweep-0: empty, blue, blue, green", make_sweep_zero_ang);
draw_row(canvas, "sweep-45: empty, blue, blue, red 45 degree sector then green",
make_sweep);
draw_row(canvas, "2pt-conic-0: empty, blue, blue, green", make_2pt_conic_zero_rad);
draw_row(canvas, "2pt-conic-1: empty, blue, blue, full red circle on green",
make_2pt_conic);
}
private:
typedef skiagm::GM INHERITED;
};
DEF_GM(return new DegenerateGradientGM;)