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Add localmatrix w/ perspective GM

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Bug: skia:10314
Change-Id: I073c8be1d0bd4d3f2f678d8963bd05ec396cd163
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/293564
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
This commit is contained in:
Michael Ludwig 2020-06-02 12:55:10 -04:00 committed by Skia Commit-Bot
parent 2ad3dfb46b
commit 5c51f5f05f
1 changed files with 97 additions and 0 deletions
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97
gm/localmatrixshader.cpp
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@ -19,6 +19,8 @@
#include "include/core/SkShader.h"
#include "include/core/SkSurface.h"
#include "include/core/SkTypes.h"
#include "include/effects/SkGradientShader.h"
#include "tools/Resources.h"
#include "tools/ToolUtils.h"
static sk_sp<SkImage> make_image(SkCanvas* rootCanvas) {
@ -109,3 +111,98 @@ DEF_SIMPLE_GM(localmatrixshader_nested, canvas, 450, 1200) {
canvas->scale(2, 2);
drawColumn();
}
DEF_SIMPLE_GM(localmatrixshader_persp, canvas, 542, 266) {
auto image = GetResourceAsImage("images/yellow_rose.png");
SkBitmap downsized;
downsized.allocPixels(image->imageInfo().makeWH(128, 128));
image->scalePixels(downsized.pixmap(), kLow_SkFilterQuality);
image = SkImage::MakeFromBitmap(downsized);
SkRect imgRect = SkRect::MakeIWH(image->width(), image->height());
// scale matrix
SkMatrix scale = SkMatrix::Scale(1.f / 5.f, 1.f / 5.f);
// perspective matrix
SkPoint src[4];
imgRect.toQuad(src);
SkPoint dst[4] = {{0, 10.f},
{image->width() + 28.f, -100.f},
{image->width() - 28.f, image->height() + 100.f},
{0.f, image->height() - 10.f}};
SkMatrix persp;
SkAssertResult(persp.setPolyToPoly(src, dst, 4));
// combined persp * scale
SkMatrix perspScale = SkMatrix::Concat(persp, scale);
auto draw = [&](sk_sp<SkShader> shader, bool applyPerspToCTM) {
canvas->save();
canvas->clipRect(imgRect);
if (applyPerspToCTM) {
canvas->concat(persp);
}
SkPaint imgShaderPaint;
imgShaderPaint.setShader(std::move(shader));
canvas->drawPaint(imgShaderPaint);
canvas->restore();
canvas->translate(10.f + image->width(), 0.f); // advance
};
// SkImageShader
canvas->save();
// 4 variants that all attempt to apply sample at persp * scale w/ an image shader
// 1. scale provided to SkImage::makeShader(...) but drawn with persp
auto s1 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, &scale);
draw(s1, true);
// 2. persp provided to SkImage::makeShader, then wrapped in scale makeWithLocalMatrix
// These pre-concat, so it ends up as persp * scale.
auto s2 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, &persp)
->makeWithLocalMatrix(scale);
draw(s2, false);
// 3. Providing pre-computed persp*scale to SkImage::makeShader()
auto s3 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, &perspScale);
draw(s3, false);
// 4. Providing pre-computed persp*scale to makeWithLocalMatrix
auto s4 = image->makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat)
->makeWithLocalMatrix(perspScale);
draw(s4, false);
canvas->restore();
canvas->translate(0.f, 10.f + image->height()); // advance to next row
// SkGradientShader
const SkColor kGradColors[] = { SK_ColorBLACK, SK_ColorTRANSPARENT };
canvas->save();
// 1. scale provided to Make, drawn with persp
auto g1 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
imgRect.width() / 2.f, kGradColors, nullptr, 2,
SkTileMode::kRepeat, 0, &scale);
draw(g1, true);
// 2. persp provided to Make, then wrapped with makeWithLocalMatrix (pre-concat as before).
auto g2 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
imgRect.width() / 2.f, kGradColors, nullptr, 2,
SkTileMode::kRepeat, 0, &persp)
->makeWithLocalMatrix(scale);
draw(g2, false);
// 3. Provide per-computed persp*scale to Make
auto g3 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
imgRect.width() / 2.f, kGradColors, nullptr, 2,
SkTileMode::kRepeat, 0, &perspScale);
draw(g3, false);
// 4. Providing pre-computed persp*scale to makeWithLocalMatrix
auto g4 = SkGradientShader::MakeRadial({imgRect.centerX(), imgRect.centerY()},
imgRect.width() / 2.f, kGradColors, nullptr, 2,
SkTileMode::kRepeat)
->makeWithLocalMatrix(perspScale);
draw(g4, false);
canvas->restore();
}