description("Ensure correct behavior of canvas with path stroke + shadow after scaling. A blue and red checkered pattern should be displayed."); function print(message, color) { var paragraph = document.createElement("div"); paragraph.appendChild(document.createTextNode(message)); paragraph.style.fontFamily = "monospace"; if (color) paragraph.style.color = color; document.getElementById("console").appendChild(paragraph); } function shouldBeAround(a, b) { var evalA; try { evalA = eval(a); } catch(e) { evalA = e; } if (Math.abs(evalA - b) < 20) print("PASS " + a + " is around " + b , "green") else print("FAIL " + a + " is not around " + b + " (actual: " + evalA + ")", "red"); } var canvas = document.createElement('canvas'); document.body.appendChild(canvas); canvas.setAttribute('width', '600'); canvas.setAttribute('height', '600'); var ctx = canvas.getContext('2d'); ctx.scale(2, 2); ctx.shadowOffsetX = 100; ctx.shadowOffsetY = 100; ctx.strokeStyle = 'rgba(0, 0, 255, 1)'; ctx.lineWidth = 5; ctx.shadowColor = 'rgba(255, 0, 0, 1.0)'; ctx.beginPath(); ctx.moveTo(50, 50); ctx.lineTo(100, 50); ctx.lineTo(100, 100); ctx.lineTo(50, 100); ctx.lineTo(50, 50); ctx.stroke(); ctx.shadowColor = 'rgba(255, 0, 0, 0.3)'; ctx.beginPath(); ctx.moveTo(50, 150); ctx.lineTo(100, 150); ctx.lineTo(100, 200); ctx.lineTo(50, 200); ctx.lineTo(50, 150); ctx.stroke(); ctx.shadowColor = 'rgba(255, 0, 0, 1.0)'; ctx.shadowBlur = 10; ctx.beginPath(); ctx.moveTo(150, 50); ctx.lineTo(200, 50); ctx.lineTo(200, 100); ctx.lineTo(150, 100); ctx.lineTo(150, 50); ctx.stroke(); ctx.shadowColor = 'rgba(255, 0, 0, 0.6)'; ctx.beginPath(); ctx.moveTo(150, 150); ctx.lineTo(200, 150); ctx.lineTo(200, 200); ctx.lineTo(150, 200); ctx.lineTo(150, 150); ctx.stroke(); var d; // imageData.data // Verify solid shadow. d = ctx.getImageData(250, 200, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBe('d[3]', '255'); d = ctx.getImageData(300, 290, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBe('d[3]', '255'); d = ctx.getImageData(200, 250, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBe('d[3]', '255'); // Verify solid alpha shadow. d = ctx.getImageData(201, 405, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '76'); d = ctx.getImageData(201, 500, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '76'); d = ctx.getImageData(300, 499, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '76'); // Verify blurry shadow. d = ctx.getImageData(398, 210, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '200'); d = ctx.getImageData(508, 250, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '49'); d = ctx.getImageData(450, 198, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '199'); // Verify blurry alpha shadow. d = ctx.getImageData(505, 450, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '70'); d = ctx.getImageData(505, 450, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '70'); d = ctx.getImageData(450, 405, 1, 1).data; shouldBe('d[0]', '255'); shouldBe('d[1]', '0'); shouldBe('d[2]', '0'); shouldBeAround('d[3]', '69');