HTML5 Canvas编写五彩连珠(1):预览
HTML5推出也有很长一段时间了,一直没有学习过,闲来无事学习开发个游戏吧。 用javascript+canvas编写一个 五彩连珠的游戏。
Canvas 画布
标签<canvas id="canvas" ></canvas>,很简单和普通的tag没区别。 关键在于js对他的操作。先看个示例代码:
<canvas id="canvas" height="100" width="100"></canvas>
<script>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.beginPath();
ctx.moveTo(50,10);
ctx.lineTo(50,90);
ctx.moveTo(10,50);
ctx.lineTo(90,50);
ctx.strokeStyle="red";
ctx.stroke();
</script>
你能看到想到我画的是什么吗? ctx是canvas的绘制的类型2D的,以后会支持3D,那木,目前基于canvas的绘制都是调用2d context的方法。所以要了解绘制各种图形,得先看看他的api。
inte易做图ce CanvasRenderingContext2D {
// back-reference to the canvas
readonly attribute HTMLCanvasElement canvas;
// state
void save(); // push state on state stack
void restore(); // pop state stack and restore state
// transformations (default transform is the identity matrix)
void scale(in double x, in double y);
void rotate(in double angle);
void translate(in double x, in double y);
void transform(in double a, in double b, in double c, in double d, in double e, in double f);
void setTransform(in double a, in double b, in double c, in double d, in double e, in double f);
// compositing
attribute double globalAlpha; // (default 1.0)
attribute DOMString globalCompositeOperation; // (default source-over)
// colors and styles
attribute any strokeStyle; // (default black)
attribute any fillStyle; // (default black)
CanvasGradient createLinearGradient(in double x0, in double y0, in double x1, in double y1);
CanvasGradient createRadialGradient(in double x0, in double y0, in double r0, in double x1, in double y1, in double r1);
CanvasPattern createPattern(in HTMLImageElement image, in DOMString repetition);
CanvasPattern createPattern(in HTMLCanvasElement image, in DOMString repetition);
CanvasPattern createPattern(in HTMLVideoElement image, in DOMString repetition);
// line caps/joins
attribute double lineWidth; // (default 1)
attribute DOMString lineCap; // "butt", "round", "square" (default "butt")
attribute DOMString lineJoin; // "round", "bevel", "miter" (default "miter")
attribute double miterLimit; // (default 10)
// shadows
attribute double shadowOffsetX; // (default 0)
attribute double shadowOffsetY; // (default 0)
attribute double shadowBlur; // (default 0)
attribute DOMString shadowColor; // (default transparent black)
// rects
void clearRect(in double x, in double y, in double w, in double h);
void fillRect(in double x, in double y, in double w, in double h);
void strokeRect(in double x, in double y, in double w, in double h);
// path API
void beginPath();
void closePath();
void moveTo(in double x, in double y);
void lineTo(in double x, in double y);
void quadraticCurveTo(in double cpx, in double cpy, in double x, in double y);
void bezierCurveTo(in double cp1x, in double cp1y, in double cp2x, in double cp2y, in double x, in double y);
void arcTo(in double x1, in double y1, in double x2, in double y2, in double radius);
void rect(in double x, in double y, in double w, in double h);
void arc(in double x, in double y, in double radius, in double startAngle, in double endAngle, in optional boolean anticlockwise);
void fill();
void stroke();
void clip();
boolean isPointInPath(in double x, in double y);
// Focus management
boolean drawFocusRing(in Element element, in optional boolean canDrawCustom);
// Caret and selection management
long caretBlinkRate();
boolean setCaretSelectionRect(in Element element, in double x, in double y, in double w, in double h);
// text
attribute DOMString font; // (default 10px sans-serif)
attribute DOMString textAlign; // "start", "end", "left", "right", "center" (default: "start")
attribute DOMString textBaseline; // "top", "hanging", "middle", "alphabetic", "ideographic", "bottom" (default: "alphabetic")
void fillText(in DOMString text, in double x, in double y, in optional double maxWidth);
void strokeText(in DOMString text, in double x, in double y, in optional double maxWidth);
TextMetrics measureText(in DOMString text);
// drawing images
void drawImage(in HTMLImageElement image, in double dx, in double dy, in optional double dw, in double dh);
void drawImage(in HTMLImageElement image, in double sx, in double sy, in double sw, in double sh, in double dx, in double dy, in double dw, in double dh);
void drawImage(in HTMLCanvasElement image, in double dx, in double dy, in optional double dw, in double dh);
void drawImage(in HTMLCanvasElement image, in double sx, in double sy, in double sw, in double sh, in double dx, in double dy, in double dw, in double dh);
void drawImage(in HTMLVideoElement image, in double dx, in double dy, in optional double dw, in double dh);
void drawImage(in HTMLVideoElement image, in double sx, in double sy, in double sw, in double sh, in double dx, in double dy, in double dw, in double dh);
// pixel manipulation
ImageData createImageData(in double sw, in double sh);
ImageData createImageData(in ImageData imagedata);
ImageData getImageData(in double sx, in double sy, in double sw, in double sh);
void putImageData(in ImageData imagedata, in double dx, in double dy, in optional double dirtyX, in double dirtyY, in double dirtyWidth, in double dirtyHeight);
};
inte易做图ce CanvasGradient {
// opaque object
void addColorStop(in double offset, in DOMString color);
};
inte易做图ce CanvasPattern {
// opaque object
补充:web前端 , HTML 5 ,