网站开发合同管辖权异议,wordpress主题栏,网站开发技术试验总结,网站建设自助搭配系统算法原理
扫描线填色算法的基本思想是#xff1a;用水平扫描线从上到下扫描由点线段构成的多段构成的多边形。每根扫描线与多边形各边产生一系列交点。将这些交点按照x坐标进行分类#xff0c;将分类后的交点成对取出#xff0c;作为两个端点#xff0c;以所填的色彩画水平…算法原理
扫描线填色算法的基本思想是用水平扫描线从上到下扫描由点线段构成的多段构成的多边形。每根扫描线与多边形各边产生一系列交点。将这些交点按照x坐标进行分类将分类后的交点成对取出作为两个端点以所填的色彩画水平直线。多边形被扫描完毕后填色也就完成。
效果 !DOCTYPE html
html langen
head
meta charsetUTF-8
meta nameviewport contentwidthdevice-width, initial-scale1.0
titleScanline Seed Fill Algorithm/title
stylecanvas {border: 1px solid black;}
/style
/head
body
canvas idcanvas width400 height400/canvas
br/
canvas idcanvasFill width400 height400/canvas
script// Define the pathconst path [{ x: 100, y: 100 },{ x: 300, y: 100 },{ x: 200, y: 200 },{x:200,y:300}];// Function to sort points by x-coordinatefunction sortByX(a, b) {return a.x - b.x;}// Function to find minimum and maximum y-coordinate in a list of pointsfunction findMinMaxY(points) {let minY points[0].y;let maxY points[0].y;for (let i 1; i points.length; i) {minY Math.min(minY, points[i].y);maxY Math.max(maxY, points[i].y);}return { minY, maxY };}// Scanline seed fill algorithmfunction seedFill(canvas, path, fillColor) {const ctx canvas.getContext(2d);const { minY, maxY } findMinMaxY(path);const imageData ctx.getImageData(0, 0, canvas.width, canvas.height);const imageDataArray imageData.data;for (let y minY; y maxY; y) {const intersections [];for (let i 0; i path.length; i) {const p1 path[i];const p2 path[(i 1) % path.length];if ((p1.y y p2.y y) || (p2.y y p1.y y)) {const x Math.round(p1.x (y - p1.y) * (p2.x - p1.x) / (p2.y - p1.y));intersections.push(x);}}intersections.sort((a, b) a - b);for (let i 0; i intersections.length; i 2) {const x1 intersections[i];const x2 intersections[i 1];for (let x x1; x x2; x) {const index (y * canvas.width x) * 4;imageDataArray[index] fillColor.r;imageDataArray[index 1] fillColor.g;imageDataArray[index 2] fillColor.b;imageDataArray[index 3] fillColor.a;}}}const canvasFill document.getElementById(canvasFill);const ctxFill canvasFill.getContext(2d);ctxFill.putImageData(imageData, 0, 0);}// Draw the pathfunction drawPath(canvas, path) {const ctx canvas.getContext(2d);ctx.beginPath();ctx.moveTo(path[0].x, path[0].y);for (let i 1; i path.length; i) {ctx.lineTo(path[i].x, path[i].y);}ctx.closePath();ctx.stroke();}// Fill the pathfunction fillPath(canvas, path) {const ctx canvas.getContext(2d);const fillColor { r: 255, g: 0, b: 0, a: 255 }; // Red color// Draw the pathdrawPath(canvas, path);// Seed fill the pathseedFill(canvas, path, fillColor);}// Fill the path on canvas loadconst canvas document.getElementById(canvas);fillPath(canvas, path);
/script
/body
/html
