skia2/gm/labyrinth.cpp
Mike Reed e9d783c4d2 use pathbuilder
Change-Id: I4b40107b45cd829595e89d75e19fd063acee4221
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/311106
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
2020-08-17 22:05:00 +00:00

99 lines
2.8 KiB
C++

/*
* Copyright 2019 Google LLC.
*
* 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/SkCanvas.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPathBuilder.h"
/**
* Repro case for https://bugs.chromium.org/p/chromium/issues/detail?id=913223
*
* The original bug was filed against square caps, but here we also draw the labyrinth using round
* and butt caps.
*
* Square and round caps expose over-coverage on overlaps when using coverage counting.
*
* Butt caps expose under-coverage on abutted strokes when using a 'max()' coverage function.
*/
static void draw_labyrinth(SkCanvas* canvas, SkPaint::Cap cap) {
constexpr static bool kRows[11][12] = {
{1,1,1,1,1,1,1,1,1,1,1,1},
{0,1,0,1,0,1,0,0,0,0,1,1},
{0,0,0,0,1,0,0,0,0,1,1,1},
{1,0,1,0,0,0,0,1,0,0,0,0},
{0,1,1,0,0,0,0,0,0,1,1,1},
{1,0,0,1,0,0,0,0,1,1,1,0},
{0,1,0,1,1,1,0,0,1,1,1,0},
{1,0,1,0,1,1,1,1,0,1,1,1},
{0,0,1,0,0,1,0,0,0,0,0,1},
{0,1,1,1,0,0,1,1,1,1,0,0},
{1,1,1,1,1,1,1,1,1,1,1,1},
};
constexpr static bool kCols[13][10] = {
{1,1,1,1,0,1,1,1,1,1},
{0,0,1,0,0,0,1,1,1,0},
{0,1,1,0,1,1,1,0,0,1},
{1,1,0,0,0,0,1,0,1,0},
{0,0,1,0,1,0,0,0,0,1},
{0,0,1,1,1,0,0,0,1,0},
{0,1,0,1,1,1,0,0,0,0},
{1,1,1,0,1,1,1,0,1,0},
{1,1,0,1,1,0,0,0,1,0},
{0,0,1,0,0,0,0,0,0,1},
{0,0,1,1,0,0,0,0,1,0},
{0,0,0,0,0,0,1,0,0,1},
{1,1,1,1,1,1,0,1,1,1},
};
SkPathBuilder maze;
for (size_t y = 0; y < SK_ARRAY_COUNT(kRows); ++y) {
for (size_t x = 0; x < SK_ARRAY_COUNT(kRows[0]); ++x) {
if (kRows[y][x]) {
maze.moveTo(x, y);
maze.lineTo(x+1, y);
}
}
}
for (size_t x = 0; x < SK_ARRAY_COUNT(kCols); ++x) {
for (size_t y = 0; y < SK_ARRAY_COUNT(kCols[0]); ++y) {
if (kCols[x][y]) {
maze.moveTo(x, y);
maze.lineTo(x, y+1);
}
}
}
SkPaint paint;
paint.setStyle(SkPaint::kStroke_Style);
paint.setStrokeWidth(.1f);
paint.setColor(0xff406060);
paint.setAntiAlias(true);
paint.setStrokeCap(cap);
canvas->translate(10.5, 10.5);
canvas->scale(40, 40);
canvas->drawPath(maze.detach(), paint);
}
constexpr static int kWidth = 500;
constexpr static int kHeight = 420;
DEF_SIMPLE_GM(labyrinth_square, canvas, kWidth, kHeight) {
draw_labyrinth(canvas, SkPaint::kSquare_Cap);
}
DEF_SIMPLE_GM(labyrinth_round, canvas, kWidth, kHeight) {
draw_labyrinth(canvas, SkPaint::kRound_Cap);
}
DEF_SIMPLE_GM(labyrinth_butt, canvas, kWidth, kHeight) {
draw_labyrinth(canvas, SkPaint::kButt_Cap);
}