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// What portion of the image width will be taken up by the magnifier.
var MAGNIFIER_WIDTH_FACTOR = 0.66;
angular.module('diff_viewer', []).directive('imgCompare', function() {
// Custom directive for comparing (3-way) images
return {
restrict: 'E', // The directive can be used as an element name
replace: true, // The directive replaces itself with the template
template: '<canvas/>',
scope: true,
link: function(scope, elm, attrs, ctrl) {
var image = new Image();
var canvas = elm[0];
var ctx = canvas.getContext('2d');
var magnifyContent = false;
// When the type attribute changes, set magnifyContent appropriately.
attrs.$observe('type', function(value) {
switch(attrs.type) {
case "differingPixelsInWhite":
magnifyContent = true;
break;
case "differencePerPixel":
break;
case "baseline":
magnifyContent = true;
break;
case "test":
magnifyContent = true;
break;
default:
console.log("Unknown type attribute on <img-compare>: " + value);
return;
}
});
// Reset ImageController's scale and render the image;
// we need to do this whenever attrs.src or attrs.width changes.
scope.setScaleAndRender = function() {
// compute the scaled image width/height for image and canvas
scope.setImgScale(image.width, attrs.width);
// Set canvas to correct size
canvas.width = image.width / scope.imgScaleDivisor;
canvas.height = image.height / scope.imgScaleDivisor;
scope.renderImage();
};
attrs.$observe('src', function(value) {
image.src = attrs.src;
image.onload = scope.setScaleAndRender;
});
attrs.$observe('width', scope.setScaleAndRender);
// When the magnify attribute changes, render the magnified rect at
// the default zoom level.
scope.$watch('magnifyCenter', function(magCenter) {
if (!magnifyContent) {
return;
}
scope.renderImage();
if (!magCenter) {
return;
}
var magX = magCenter.x - scope.magnifierHalfWidth;
var magY = magCenter.y - scope.magnifierHalfHeight;
var magMaxX = canvas.width - scope.magnifierWidth;
var magMaxY = canvas.height - scope.magnifierHeight;
var magRect = { x: Math.max(0, Math.min(magX, magMaxX)),
y: Math.max(0, Math.min(magY, magMaxY)),
width: scope.magnifierWidth,
height: scope.magnifierHeight
};
var imgRect = { x: (magCenter.x * scope.imgScaleDivisor) - scope.magnifierHalfWidth,
y: (magCenter.y * scope.imgScaleDivisor) - scope.magnifierHalfHeight,
width: scope.magnifierWidth,
height: scope.magnifierHeight
};
// draw the magnified image
ctx.clearRect(magRect.x, magRect.y, magRect.width, magRect.height);
ctx.drawImage(image, imgRect.x, imgRect.y, imgRect.width, imgRect.height,
magRect.x, magRect.y, magRect.width, magRect.height);
// draw the outline rect
ctx.beginPath();
ctx.rect(magRect.x, magRect.y, magRect.width, magRect.height);
ctx.lineWidth = 2;
ctx.strokeStyle = 'red';
ctx.stroke();
});
// render the image to the canvas. This is often done every frame prior
// to any special effects (i.e. magnification).
scope.renderImage = function() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.drawImage(image, 0, 0, canvas.width, canvas.height);
};
// compute a rect (x,y,width,height) that represents the bounding box for
// the magnification effect
scope.computeMagnifierOutline = function(event) {
var scaledWidth = scope.magnifierWidth / scope.imgScaleDivisor;
var scaledHeight = scope.magnifierHeight / scope.imgScaleDivisor;
return {
x: event.offsetX - (scaledWidth * 0.5),
y: event.offsetY - (scaledHeight * 0.5),
width: scaledWidth,
height: scaledHeight
};
};
// event handler for mouse events that triggers the magnification
// effect across the 4 images being compared.
scope.MagnifyDraw = function(event, startMagnify) {
if (startMagnify) {
scope.setMagnifierState(true);
} else if (!scope.magnifierOn) {
return;
}
scope.renderImage();
// render the magnifier outline rect
var rect = scope.computeMagnifierOutline(event);
ctx.save();
ctx.beginPath();
ctx.rect(rect.x, rect.y, rect.width, rect.height);
ctx.lineWidth = 2;
ctx.strokeStyle = 'red';
ctx.stroke();
ctx.restore();
// update scope on baseline / test that will cause them to render
scope.setMagnifyCenter({x: event.offsetX, y: event.offsetY});
};
// event handler that triggers the end of the magnification effect and
// resets all the canvases to their original state.
scope.MagnifyEnd = function(event) {
scope.renderImage();
// update scope on baseline / test that will cause them to render
scope.setMagnifierState(false);
scope.setMagnifyCenter(undefined);
};
}
};
});
function ImageController($scope, $http, $location, $timeout, $parse) {
$scope.imgScaleDivisor = 1.0;
$scope.magnifierOn = false;
$scope.magnifyCenter = undefined;
$scope.setImgScale = function(srcImageWidth, displayWidth) {
$scope.imgScaleDivisor = srcImageWidth / displayWidth;
$scope.magnifierWidth = displayWidth * MAGNIFIER_WIDTH_FACTOR;
$scope.magnifierHeight = $scope.magnifierWidth;
$scope.magnifierHalfWidth = $scope.magnifierWidth / 2;
$scope.magnifierHalfHeight = $scope.magnifierHeight / 2;
}
$scope.setMagnifierState = function(magnifierOn) {
$scope.magnifierOn = magnifierOn;
}
$scope.setMagnifyCenter = function(magnifyCenter) {
$scope.magnifyCenter = magnifyCenter;
}
}
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