More MDC tests

test/public/tests.js

@@ -143,6 +143,75 @@ tests['translate()'] = function(ctx){
   }
 };
 
+tests['scale()'] = function(ctx){
+  ctx.strokeStyle = "#fc0";
+  ctx.lineWidth = 1.5;
+  ctx.fillRect(0,0,300,300);
+
+  // Uniform scaling
+  ctx.save()
+  ctx.translate(50,50);
+  drawSpirograph(ctx,22,6,5);  // no scaling
+
+  ctx.translate(100,0);
+  ctx.scale(0.75,0.75);
+  drawSpirograph(ctx,22,6,5);
+
+  ctx.translate(133.333,0);
+  ctx.scale(0.75,0.75);
+  drawSpirograph(ctx,22,6,5);
+  ctx.restore();
+
+  // Non-uniform scaling (y direction)
+  ctx.strokeStyle = "#0cf";
+  ctx.save()
+  ctx.translate(50,150);
+  ctx.scale(1,0.75);
+  drawSpirograph(ctx,22,6,5);
+
+  ctx.translate(100,0);
+  ctx.scale(1,0.75);
+  drawSpirograph(ctx,22,6,5);
+
+  ctx.translate(100,0);
+  ctx.scale(1,0.75);
+  drawSpirograph(ctx,22,6,5);
+  ctx.restore();
+
+  // Non-uniform scaling (x direction)
+  ctx.strokeStyle = "#cf0";
+  ctx.save()
+  ctx.translate(50,250);
+  ctx.scale(0.75,1);
+  drawSpirograph(ctx,22,6,5);
+
+  ctx.translate(133.333,0);
+  ctx.scale(0.75,1);
+  drawSpirograph(ctx,22,6,5);
+
+  ctx.translate(177.777,0);
+  ctx.scale(0.75,1);
+  drawSpirograph(ctx,22,6,5);
+  ctx.restore();
+  function drawSpirograph(ctx,R,r,O){
+    var x1 = R-O;
+    var y1 = 0;
+    var i  = 1;
+    ctx.beginPath();
+    ctx.moveTo(x1,y1);
+    do {
+      if (i>20000) break;
+      var x2 = (R+r)*Math.cos(i*Math.PI/72) - (r+O)*Math.cos(((R+r)/r)*(i*Math.PI/72))
+      var y2 = (R+r)*Math.sin(i*Math.PI/72) - (r+O)*Math.sin(((R+r)/r)*(i*Math.PI/72))
+      ctx.lineTo(x2,y2);
+      x1 = x2;
+      y1 = y2;
+      i++;
+    } while (x2 != R-O && y2 != 0 );
+    ctx.stroke();
+  }
+};
+
 tests['rect()'] = function(ctx){
   ctx.rect(5,5,50,50);
   ctx.strokeStyle = 'yellow';