var canvas = dygraph.hidden_;
var ctx = canvas.getContext("2d");
this.imageData_ = ctx.getImageData(0, 0, canvas.width, canvas.height);
+ this.scale = canvas.width / dygraph.width_;
};
/**
* are in [0, 255]. A pixel which has never been touched will be [0,0,0,0].
*/
PixelSampler.prototype.colorAtPixel = function(x, y) {
- var i = 4 * (x + this.imageData_.width * y);
+ var i = 4 * (x * this.scale + this.imageData_.width * y * this.scale);
var d = this.imageData_.data;
return [d[i], d[i+1], d[i+2], d[i+3]];
};