piskel/js/utils/PixelUtils.js

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(function () {
var ns = $.namespace("pskl");
ns.PixelUtils = {
getRectanglePixels : function (x0, y0, x1, y1) {
var rectangle = this.getOrderedRectangleCoordinates(x0, y0, x1, y1);
var pixels = [];
for(var x = rectangle.x0; x <= rectangle.x1; x++) {
for(var y = rectangle.y0; y <= rectangle.y1; y++) {
pixels.push({"col": x, "row": y});
}
}
return pixels;
},
getBoundRectanglePixels : function (x0, y0, x1, y1) {
var rectangle = this.getOrderedRectangleCoordinates(x0, y0, x1, y1);
var pixels = [];
// Creating horizontal sides of the rectangle:
for(var x = rectangle.x0; x <= rectangle.x1; x++) {
pixels.push({"col": x, "row": rectangle.y0});
pixels.push({"col": x, "row": rectangle.y1});
}
// Creating vertical sides of the rectangle:
for(var y = rectangle.y0; y <= rectangle.y1; y++) {
pixels.push({"col": rectangle.x0, "row": y});
pixels.push({"col": rectangle.x1, "row": y});
}
return pixels;
},
/**
* Return an object of ordered rectangle coordinate.
* In returned object {x0, y0} => top left corner - {x1, y1} => bottom right corner
* @private
*/
getOrderedRectangleCoordinates : function (x0, y0, x1, y1) {
return {
x0 : Math.min(x0, x1),
y0 : Math.min(y0, y1),
x1 : Math.max(x0, x1),
y1 : Math.max(y0, y1)
};
},
/**
* Return the list of pixels that would have been filled by a paintbucket tool applied
* on pixel at coordinate (x,y).
* This function is not altering the Frame object argument.
*
* @param frame pskl.model.Frame The frame target in which we want to paintbucket
* @param col number Column coordinate in the frame
* @param row number Row coordinate in the frame
*
* @return an array of the pixel coordinates paint with the replacement color
*/
getSimilarConnectedPixelsFromFrame: function(frame, col, row) {
// To get the list of connected (eg the same color) pixels, we will use the paintbucket algorithm
// in a fake cloned frame. The returned pixels by the paintbucket algo are the painted pixels
// and are as well connected.
var fakeFrame = frame.clone(); // We just want to
var fakeFillColor = "sdfsdfsdf"; // A fake color that will never match a real color.
var paintedPixels = this.paintSimilarConnectedPixelsFromFrame(fakeFrame, col, row, fakeFillColor);
return paintedPixels;
},
/**
* Apply the paintbucket tool in a frame at the (col, row) initial position
* with the replacement color.
*
* @param frame pskl.model.Frame The frame target in which we want to paintbucket
* @param col number Column coordinate in the frame
* @param row number Row coordinate in the frame
* @param replacementColor string Hexadecimal color used to fill the area
*
* @return an array of the pixel coordinates paint with the replacement color
*/
paintSimilarConnectedPixelsFromFrame: function(frame, col, row, replacementColor) {
/**
* Queue linear Flood-fill (node, target-color, replacement-color):
* 1. Set Q to the empty queue.
* 2. If the color of node is not equal to target-color, return.
* 3. Add node to Q.
* 4. For each element n of Q:
* 5. If the color of n is equal to target-color:
* 6. Set w and e equal to n.
* 7. Move w to the west until the color of the node to the west of w no longer matches target-color.
* 8. Move e to the east until the color of the node to the east of e no longer matches target-color.
* 9. Set the color of nodes between w and e to replacement-color.
* 10. For each node n between w and e:
* 11. If the color of the node to the north of n is target-color, add that node to Q.
* 12. If the color of the node to the south of n is target-color, add that node to Q.
* 13. Continue looping until Q is exhausted.
* 14. Return.
*/
var paintedPixels = [];
var queue = [];
var dy = [-1, 0, 1, 0];
var dx = [0, 1, 0, -1];
var targetColor;
try {
targetColor = frame.getPixel(col, row);
} catch(e) {
// Frame out of bound exception.
}
if(targetColor == replacementColor) {
return;
}
queue.push({"col": col, "row": row});
var loopCount = 0;
var cellCount = frame.getWidth() * frame.getHeight();
while(queue.length > 0) {
loopCount ++;
var currentItem = queue.pop();
frame.setPixel(currentItem.col, currentItem.row, replacementColor);
paintedPixels.push({"col": currentItem.col, "row": currentItem.row });
for (var i = 0; i < 4; i++) {
var nextCol = currentItem.col + dx[i];
var nextRow = currentItem.row + dy[i];
try {
if (frame.containsPixel(nextCol, nextRow) && frame.getPixel(nextCol, nextRow) == targetColor) {
queue.push({"col": nextCol, "row": nextRow });
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}
} catch(e) {
// Frame out of bound exception.
}
}
// Security loop breaker:
if(loopCount > 10 * cellCount) {
console.log("loop breaker called");
break;
}
}
return paintedPixels;
},
/**
* Calculate and return the maximal DPI to display a picture in a given container.
*
* @param container jQueryObject Container where the picture should be displayed
* @param number pictureHeight height in pixels of the picture to display
* @param number pictureWidth width in pixels of the picture to display
* @return number maximal dpi
*/
calculateDPIForContainer : function (container, pictureHeight, pictureWidth) {
return this.calculateDPI(container.height(), container.width(), pictureHeight, pictureWidth);
},
/**
* Calculate and return the maximal DPI to display a picture for a given height and width.
*
* @param height number Height available to display the picture
* @param width number Width available to display the picture
* @param number pictureHeight height in pixels of the picture to display
* @param number pictureWidth width in pixels of the picture to display
* @return number maximal dpi
*/
calculateDPI : function (height, width, pictureHeight, pictureWidth) {
var heightBoundDpi = Math.floor(height / pictureHeight),
widthBoundDpi = Math.floor(width / pictureWidth);
return Math.min(heightBoundDpi, widthBoundDpi);
}
};
})();