javascript - html5 canvas, image as background for arch or circle -


hello stackoverflow people, first post here.

i have circle on canvas, , circle divided sky , ground portion, , (analog) clock looking, imagine hands of clock extended edge of circle, making 2 'pie slices'. , hands moving. have different (background) images 2 portions. have gradiant fill, change gradiant appropriate images. images must fill whole portion of 'pie slice'. code far:

  // ground portion of circle   var lingrad=ctx.createlineargradient(center.x, center.y,center.x,main_radius*2);   lingrad.addcolorstop(0,'green');   lingrad.addcolorstop(1,'brown');   ctx.fillstyle=lingrad;   ctx.beginpath();   ctx.moveto(center.x, center.y);   ctx.lineto(x2, y2);   ctx.arc(center.x, center.y, radius,  d2r(z1 + 90), d2r(v1 + 90), false);   ctx.moveto(center.x, center.y);   ctx.lineto(x1, y1);   ctx.closepath();   ctx.fill();   // sky portion of circle   var lingrad1=ctx.createlineargradient(center.x,0,center.x,center.y);   lingrad1.addcolorstop(0,'yellow');   lingrad1.addcolorstop(0.5,'yellow');   lingrad1.addcolorstop(1,'cyan');   ctx.fillstyle=lingrad1;   ctx.beginpath();   ctx.moveto(center.x, center.y);   ctx.lineto(x2, y2);   ctx.arc(center.x, center.y, radius,  d2r(z1 + 90), d2r(v1 + 90), true);   ctx.moveto(center.x, center.y);   ctx.lineto(x1, y1);   ctx.closepath();   ctx.fill();

thank , sorry english

you can use example clip() first defining clip path using arc(), call clip(), draw in 2 images in each half.

a simple example:

var img1 = new image, img2 = new image, count = 0, ctx = c.getcontext("2d");  img1.onload = img2.onload = go;  img1.src = "//i.stack.imgur.com/eu6kb.jpg";  img2.src = "//i.stack.imgur.com/umea9.jpg";    function go() {    if (++count < 2) return;  // make sure both images has loaded        // save state restoring way remove clip-mask    ctx.save();        // define clip-mask using path operations    ctx.arc(75, 75, 75, 0, 6.28);    ctx.clip();        // draw in top image    ctx.drawimage(img1, 0, 0);      // draw in bottom image    ctx.drawimage(img2, 0, 75);        // remove clip mask    ctx.restore();  }
<canvas id=c></canvas>

you can of course use position, size clipping arguments of drawimage() taste.


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