YUI2 ColorPicker default value issue - javascript

I'm using the YUI2 colour picker on a project to provide a theme/colour scheme changing functionality. I'm setting the default rgb value of each colour picker to the current rgb value of an element of the colour scheme.
The rgb value that the picker holds is fine, however the Hue Slider and Picker Slider are not updating to reflect this. Whenever the colour picker appears the hue and picker are set to 0 and ffffff respectively.
I've searched through the documentation and tried a few likely methods that might update the hue/picker slider appropriately, with no luck.
Any advice would be greatly appreciated

After some more searching and playing around I managed to come up with a solution. There are two steps to the process;
Step 1
You need to compute the HSV (Hue, Saturation, Value) from the rgb value. This is done using the function rgbTohsv() below, which I got here. Its been modified from the original to account for the way the YUI HueSlider and PickerSlider expect input.
function rgbTohsv (rgb) {
var computedH = computedS = computedV = 0;
//remove spaces from input RGB values, convert to int
var r = parseInt( (''+rgb[0]).replace(/\s/g,''),10 );
var g = parseInt( (''+rgb[1]).replace(/\s/g,''),10 );
var b = parseInt( (''+rgb[2]).replace(/\s/g,''),10 );
r=r/255; g=g/255; b=b/255;
var minRGB = Math.min(r,Math.min(g,b));
var maxRGB = Math.max(r,Math.max(g,b));
// Black-gray-white
if (minRGB==maxRGB) {
computedV = minRGB;
return [0,0,Math.round(computedV*100)];
}
// Colors other than black-gray-white:
var d = (r==minRGB) ? g-b : ((b==minRGB) ? r-g : b-r);
var h = (r==minRGB) ? 3 : ((b==minRGB) ? 1 : 5);
computedH = 60*(h - d/(maxRGB - minRGB));
computedS = (maxRGB - minRGB)/maxRGB;
computedV = maxRGB;
return [(360-computedH)/2,Math.round(computedS*100),Math.round(computedV*100)];
}
Modifications:: The hue slider expects a value between 180-0, rather than the usual 0-360. As well as the shorter range it is also inverted so it goes from 180->0. The S and V values must be an integer between 0-100, whereas the original function returned 0-1.0 values. Both of these issues have been accounted for in the above function.
Step 2
Next you need to set the hsv values of the colour picker., so where colourPicker is your initialised colour picker variable;
hsv = rgbTohsv(rgb);
colourPicker.hueSlider.setValue(hsv[0],0);
colourPicker.pickerSlider.setRegionValue(hsv[1],hsv[2]);
By default updating the hue slider and picker slider do an animation when updated, you can suppress this by adding a false variable at the end of the method call.
colourPicker.hueSlider.setValue(hsv[0],0,true);
colourPicker.pickerSlider.setRegionValue(hsv[1],hsv[2], true);

Related

How to set background color of a button as the THREE js textGeometry color?

I'm trying to set the background color of a button to a THREE JS textGeometry color.
var element = event.target;
var hexColor = $(element).css("background-color");
Here the onclick of the button is saved and its background is stored in the hexColor variable.
var parse = hexColor.toLowerCase().match(/^rgba?\((\d+),\s*(\d+),\s*(\d+)
(?:,\s*(\d+(?:\.\d+)?))?\)$/);
var rgbColor = {
r : parseInt(parse[1]),
g : parseInt(parse[2]),
b : parseInt(parse[3])
};
activeElement.material.color = rgbColor;
The output of the parse is an array of size 6 with r,g,b values as strings.After that, I parse the corresponding values to integer and save as an object.When I set the object as the material color of the active textGeometry element, It will become white...No other colors are visible.Is this the correct method?

OpenLayers 3 change point fill color depending on feature parameter value?

I'm populating my map with geojson and all my points have a feature parameter with a specific numeric value. It's a map with temperature values.
Each of this points will need a different fill color depending on the value.
I'm looking for ways to improve my code here. The return value will create the fill color of each point:
var tempVal = feature.get('tempertaure_value');
var tempNum = Number(tempVal.toFixed());
switch (true) {
case tempNum == -30:
return '#0e0e15';
break;
case tempNum == -29:
return '#0d131f';
break;
case tempNum == -28:
return '#0e1226';
break;
... etc ...
}
Can I create a multidimensional array that loops for a key value and returns the color value?
I would appreciate help for a better solution that what I currently have because my switch statement has become massive, up to 81 temperature values (from -30 to 50 degrees).
I would create an object like:
var colors = {
'-30': '#0e0e15',
'-29': '...',
'-28': '...'
};
To access:
// just supposing here
var tempVal = feature.get('tempertaure_value');
var color = colors[tempVal];
You could use Chroma.js. You pass the needed colors into the range method and their respective values to the domain method:
var scale = chroma.scale(['blue', 'yellow', 'red']).domain([-30, 10 , 50]);
It returns a method you can use to return a color based on the value you pass as the parameter:
scale(-30).hex(); // returns hex code for blue
scale(10).hex(); // returns hex code for yellow
scale(30).hex(); // returns hex code for orange
scale(50).hex(); // returns hex code for red
Here's an example on Plunker: http://plnkr.co/edit/k5HPfi?p=preview

pdf.js: Get the text colour

I have a simple pdf file, containing the words "Hello world", each in a different colour.
I'm loading the PDF, like this:
PDFJS.getDocument('test.pdf').then( onPDF );
function onPDF( pdf )
{
pdf.getPage( 1 ).then( onPage );
}
function onPage( page )
{
page.getTextContent().then( onText );
}
function onText( text )
{
console.log( JSON.stringify( text ) );
}
And I get a JSON output like this:
{
"items" : [{
"str" : "Hello ",
"dir" : "ltr",
"width" : 29.592,
"height" : 12,
"transform" : [12, 0, 0, 12, 56.8, 774.1],
"fontName" : "g_font_1"
}, {
"str" : "world",
"dir" : "ltr",
"width" : 27.983999999999998,
"height" : 12,
"transform" : [12, 0, 0, 12, 86.5, 774.1],
"fontName" : "g_font_1"
}
],
"styles" : {
"g_font_1" : {
"fontFamily" : "serif",
"ascent" : 0.891,
"descent" : 0.216
}
}
}
However, I've not been able to find a way to determine the colour of each word. When I render it, it renders properly, so I know the information is in there somewhere. Is there somewhere I can access this?
As Respawned alluded to, there is no easy answer that will work in all cases. That being said, here are two approaches which seem to work fairly well. Both having upsides and downsides.
Approach 1
Internally, the getTextContent method uses whats called an EvaluatorPreprocessor to parse the PDF operators, and maintain the graphic state. So what we can do is, implement a custom EvaluatorPreprocessor, overwrite the preprocessCommand method, and use it to add the current text color to the graphic state. Once this is in place, anytime a new text chunk is created, we can add a color attribute, and set it to the current color state.
The downsides to this approach are:
Requires modifying the PDFJS source code. It also depends heavily on
the current implementation of PDFJS, and could break if this is
changed.
It will fail in cases where the text is used as a path to be filled with an image. In some PDF creators (such as Photoshop), the way it creates colored text is, it first creates a clipping path from all the given text characters, and then paints a solid image over the path. So the only way to deduce the fill-color is by reading the pixel values from the image, which would require painting it to a canvas. Even hooking into paintChar wont be of much help here, since the fill color will only emerge at a later time.
The upside is, its fairly robust and works irrespective of the page background. It also does not require rendering anything to canvas, so it can be done entirely in the background thread.
Code
All the modifications are made in the core/evaluator.js file.
First you must define the custom evaluator, after the EvaluatorPreprocessor definition.
var CustomEvaluatorPreprocessor = (function() {
function CustomEvaluatorPreprocessor(stream, xref, stateManager, resources) {
EvaluatorPreprocessor.call(this, stream, xref, stateManager);
this.resources = resources;
this.xref = xref;
// set initial color state
var state = this.stateManager.state;
state.textRenderingMode = TextRenderingMode.FILL;
state.fillColorSpace = ColorSpace.singletons.gray;
state.fillColor = [0,0,0];
}
CustomEvaluatorPreprocessor.prototype = Object.create(EvaluatorPreprocessor.prototype);
CustomEvaluatorPreprocessor.prototype.preprocessCommand = function(fn, args) {
EvaluatorPreprocessor.prototype.preprocessCommand.call(this, fn, args);
var state = this.stateManager.state;
switch(fn) {
case OPS.setFillColorSpace:
state.fillColorSpace = ColorSpace.parse(args[0], this.xref, this.resources);
break;
case OPS.setFillColor:
var cs = state.fillColorSpace;
state.fillColor = cs.getRgb(args, 0);
break;
case OPS.setFillGray:
state.fillColorSpace = ColorSpace.singletons.gray;
state.fillColor = ColorSpace.singletons.gray.getRgb(args, 0);
break;
case OPS.setFillCMYKColor:
state.fillColorSpace = ColorSpace.singletons.cmyk;
state.fillColor = ColorSpace.singletons.cmyk.getRgb(args, 0);
break;
case OPS.setFillRGBColor:
state.fillColorSpace = ColorSpace.singletons.rgb;
state.fillColor = ColorSpace.singletons.rgb.getRgb(args, 0);
break;
}
};
return CustomEvaluatorPreprocessor;
})();
Next, you need to modify the getTextContent method to use the new evaluator:
var preprocessor = new CustomEvaluatorPreprocessor(stream, xref, stateManager, resources);
And lastly, in the newTextChunk method, add a color attribute:
color: stateManager.state.fillColor
Approach 2
Another approach would be to extract the text bounding boxes via getTextContent, render the page, and for each text, get the pixel values which reside within its bounds, and take that to be the fill color.
The downsides to this approach are:
The computed text bounding boxes are not always correct, and in some cases may even be off completely (eg: rotated text). If the bounding box does not cover at least partially the actual text on canvas, then this method will fail. We can recover from complete failures, by checking that the text pixels have a color variance greater than a threshold. The rationale being, if bounding box is completely background, it will have little variance, in which case we can fallback to a default text color (or maybe even the color of k nearest-neighbors).
The method assumes the text is darker than the background. Otherwise, the background could be mistaken as the fill color. This wont be a problem is most cases, as most docs have white backgrounds.
The upside is, its simple, and does not require messing with the PDFJS source-code. Also, it will work in cases where the text is used as a clipping path, and filled with an image. Though this can become hazy when you have complex image fills, in which case, the choice of text color becomes ambiguous.
Demo
http://jsfiddle.net/x2rajt5g/
Sample PDF's to test:
https://www.dropbox.com/s/0t5vtu6qqsdm1d4/color-test.pdf?dl=1
https://www.dropbox.com/s/cq0067u80o79o7x/testTextColour.pdf?dl=1
Code
function parseColors(canvasImgData, texts) {
var data = canvasImgData.data,
width = canvasImgData.width,
height = canvasImgData.height,
defaultColor = [0, 0, 0],
minVariance = 20;
texts.forEach(function (t) {
var left = Math.floor(t.transform[4]),
w = Math.round(t.width),
h = Math.round(t.height),
bottom = Math.round(height - t.transform[5]),
top = bottom - h,
start = (left + (top * width)) * 4,
color = [],
best = Infinity,
stat = new ImageStats();
for (var i, v, row = 0; row < h; row++) {
i = start + (row * width * 4);
for (var col = 0; col < w; col++) {
if ((v = data[i] + data[i + 1] + data[i + 2]) < best) { // the darker the "better"
best = v;
color[0] = data[i];
color[1] = data[i + 1];
color[2] = data[i + 2];
}
stat.addPixel(data[i], data[i+1], data[i+2]);
i += 4;
}
}
var stdDev = stat.getStdDev();
t.color = stdDev < minVariance ? defaultColor : color;
});
}
function ImageStats() {
this.pixelCount = 0;
this.pixels = [];
this.rgb = [];
this.mean = 0;
this.stdDev = 0;
}
ImageStats.prototype = {
addPixel: function (r, g, b) {
if (!this.rgb.length) {
this.rgb[0] = r;
this.rgb[1] = g;
this.rgb[2] = b;
} else {
this.rgb[0] += r;
this.rgb[1] += g;
this.rgb[2] += b;
}
this.pixelCount++;
this.pixels.push([r,g,b]);
},
getStdDev: function() {
var mean = [
this.rgb[0] / this.pixelCount,
this.rgb[1] / this.pixelCount,
this.rgb[2] / this.pixelCount
];
var diff = [0,0,0];
this.pixels.forEach(function(p) {
diff[0] += Math.pow(mean[0] - p[0], 2);
diff[1] += Math.pow(mean[1] - p[1], 2);
diff[2] += Math.pow(mean[2] - p[2], 2);
});
diff[0] = Math.sqrt(diff[0] / this.pixelCount);
diff[1] = Math.sqrt(diff[1] / this.pixelCount);
diff[2] = Math.sqrt(diff[2] / this.pixelCount);
return diff[0] + diff[1] + diff[2];
}
};
This question is actually extremely hard if you want to do it to perfection... or it can be relatively easy if you can live with solutions that work only some of the time.
First of all, realize that getTextContent is intended for searchable text extraction and that's all it's intended to do.
It's been suggested in the comments above that you use page.getOperatorList(), but that's basically re-implementing the whole PDF drawing model in your code... which is basically silly because the largest chunk of PDFJS does exactly that... except not for the purpose of text extraction but for the purpose of rendering to canvas. So what you want to do is to hack canvas.js so that instead of just setting its internal knobs it also does some callbacks to your code. Alas, if you go this way, you won't be able to use stock PDFJS, and I rather doubt that your goal of color extraction will be seen as very useful for PDFJS' main purpose, so your changes are likely not going to get accepted upstream, so you'll likely have to maintain your own fork of PDFJS.
After this dire warning, what you'd need to minimally change are the functions where PDFJS has parsed the PDF color operators and sets its own canvas painting color. That happens around line 1566 (of canvas.js) in function setFillColorN. You'll also need to hook the text render... which is rather a character renderer at canvas.js level, namely CanvasGraphics_paintChar around line 1270. With these two hooked, you'll get a stream of callbacks for color changes interspersed between character drawing sequences. So you can reconstruct the color of character sequences reasonably easy from this.. in the simple color cases.
And now I'm getting to the really ugly part: the fact that PDF has an extremely complex color model. First there are two colors for drawing anything, including text: a fill color and stroke (outline) color. So far not too scary, but the color is an index in a ColorSpace... of which there are several, RGB being only one possibility. Then there's also alpha and compositing modes, so the layers (of various alphas) can result in a different final color depending on the compositing mode. And the PDFJS has not a single place where it accumulates color from layers.. it simply [over]paints them as they come. So if you only extract the fill color changes and ignore alpha, compositing etc.. it will work but not for complex documents.
Hope this helps.
There's no need to patch pdfjs, the transform property gives the x and y, so you can go through the operator list and find the setFillColor op that precedes the text op at that point.

Fastest way to generate a color that is not in an array of colors

I'm wondering what the best way to approach this problem is...
I have an array of user defined colors that get pushed onto a stack as rgb values. I want to find a second color for each user-defined color. These second colors must be completely unique from the user-defined array, but can be completely random and do not need to have any visual relationship with any of the user colors.
Would generating random rgb values and testing it against the stack be fast, since it is highly unlikely that random numbers would find the same color on the first try. Or would simply starting at 255,254,253 and substracting 1 from each value, then testing it against the stack be better, also very unlikely and less operations. Or any other idea?
Here's some code to start off:
var colors = [];
function getRandUniqColor()
{
var r = getRGBString(),
g = getRGBString(),
b = getRGBString(),
rgb = r + g + b;
if ( colors.indexOf(rgb) == -1 )
{
colors.push(rgb);
return {
r: r,
g: g,
b: b
}
}
else
{
return getRandUniqColor()
}
}
function getRGBString()
{
var num = Math.floor( Math.random() * 255 ).toString();
while (num.length < 3)
{
num = '0' + num;
}
return num;
}
Just call getRandUniqColor(), and you'll get an object literal of RGB values.
Note: If there'll be a lot of colors involved, you should not use a recursive function.
...and here's the fiddle: http://jsfiddle.net/wV6Mw/
I would suggest generating random RGB values (combine three random numbers) and then create a function that measures the color difference between your generated random color and the ones in your data structure. If your generated color is too close to one you already have, generate a new one. You will have to decide how "different" you want the random color to be from what you already have, but a difference of only a few points in R, G an B won't be discernibly different so you should be looking for some minimum separation in at least one channel.
Searching for "calculate rgb color difference" gives you a bunch of references on how to calculate a meaningful difference between two color values. This link from that search has a specific equation and here's a previous question on SO about color differences.
You can also generate complementary colors from what you already have if you just want different colors and don't need/want truly random colors.
You could generate a random color like this in either data form or hex string form:
// generate r,g,b data structure like {r: 255, g: 30, b: 09}
function generateRandomColorData() {
function randomColorVal() {
return(Math.floor(Math.random() * 256));
}
return {r:randomColorVal(), g: randomeColorVal(), b: randomColorVal()};
}
// generate hex string color value like FF4409
function generateRandomColorHex() {
function randomColorVal() {
var val = Math.floor(Math.random() * 256).toString(16);
if (val.length < 2) {
val = "0" + val;
}
return(val);
}
return(randomColorVal() + randomColorVal() + randomColorVal());
}
As others have said, the easiest way would probably be to just create random colors and check for collisions.
If you are filling up the color space a lot (users selecting millions of colors) then another way would be to create a color cube of 256^3 bits, and let "1" represent the used colors. Then you could start from position 0 and use the first "0" as your generated color, the next "0" as the second and so on. The data structure would be just over 2 MB of ram.
But random is probably the way to go.

YUI API Dual Slider control question

I'm using the YUI 2.7 library to handle a dual-slider (range slider) control in a webpage.
It works great-- however, I wanted to allow users to switch the range values by Ajax-- effectively changing the price range from "0-50,000" to a subset (eg. "50-250") without reloading the page.
The problem is that it appears the values from the existing slider do not get reset, even when I explicitly set them back to NULL inside the function to "rebuild" the slider.
The slider handles appear out of position after the ajax request, (way off the scale to the right) and the values of the slider apparently randomly fluctuate.
Is there a way to explicitly destroy the YUI slider object, beyond setting its reference to null? Or do I just need to redeclare the scale and min/max values somehow?
Thanks for any help (I'll try to post a link to an example asap)
here's the code:
function slider(bg,minthumb,maxthumb,minvalue,maxvalue,startmin,startmax,aSliderName,soptions) {
var scaleFactor = null;
var tickSize = null;
var range = null;
var dual_slider = null;
var initVals = null;
var Dom = null;
range = options.sliderLength;
if ((startmax - startmin) < soptions.sliderLength) {
tickSize = (soptions.sliderLength / (startmax - startmin));
}else{
tickSize = 1;
}
initVals = [ 0,soptions.sliderLength ], // Values assigned during instantiation
//Event = YAHOO.util.Event,
dual_slider,
scaleFactor = ((startmax - startmin) / soptions.sliderLength);
dual_slider = YAHOO.widget.Slider.getHorizDualSlider(
bg,minthumb,maxthumb,range, tickSize, initVals);
dual_slider.subscribe("change", function(instance) {
priceMin = (dual_slider.minVal * scaleFactor) + startmin;
priceMax = (dual_slider.maxVal * scaleFactor) + startmin;
});
dual_slider.subscribe("slideEnd", function(){ alert(priceMin + ' ' + priceMax); });
return dual_slider;
}
Store the startmin, startmax, and scaleFactor on the dual_slider object, then in your ajax callback, update those properties with new values. Change your change event subscriber to reference this.startmin, this.startmax, and this.scaleFactor.
Slider and DualSlider only really understand the pixel offsets of the thumbs, and report the values as such. As you've done (and per most Slider examples), you need to apply a conversion factor to translate a pixel offset to a "value". This common idiom has been rolled into the core logic of the YUI 3 Slider (though there isn't yet a DualSlider in the library).
Here's an example that illustrates dynamically updating value ranges:
http://yuiblog.com/sandbox/yui/v282/examples/slider/slider_factor_change.html

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