Nine-patch images for web development [closed] - html

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I'm wondering if there is something like 9-patch in Android, but for web development?
Disclosure: I have no idea about web development at all, but I was curious to know if it exists. And a simple web search with the term 9-patch didn't bring up any related results, so I figured it has either another term or it doesn't exist or is not used widely enough.
Anyone knows?

Answer 1

Yes. It is used for border-image in CSS 3:
http://www.css3.info/preview/border-image/
http://www.w3.org/TR/css3-background/#border-images

Answer 2

If you're still interested I created a Javascript file that uses canvas to create real nine patch image support for the web. The open source project can be found here:
https://github.com/chrislondon/9-Patch-Image-for-Websites

Answer 3

Well, I took the trouble to correct deserts errors I found in the link above.
Knowing NinePath android is a useful tool adding dynamic painting and recognition of padding (which was missing in the previous pluying). I could add one few scripts for complete functionality.
Replace the following code in the library path9.js!
function NinePatchGetStyle(element, style)
{
if (window.getComputedStyle)
{
var computedStyle = window.getComputedStyle(element, "");
if (computedStyle === null)
return "";
return computedStyle.getPropertyValue(style);
}
else if (element.currentStyle)
{
return element.currentStyle[style];
}
else
{
return "";
}
}
// Cross browser function to find valid property
function NinePatchGetSupportedProp(propArray)
{
var root = document.documentElement; //reference root element of document
for (var i = 0; i < propArray.length; i++)
{
// loop through possible properties
if (typeof root.style[propArray[i]] === "string")
{
//if the property value is a string (versus undefined)
return propArray[i]; // return that string
}
}
return false;
}
/**
* 9patch constructer. Sets up cached data and runs initial draw.
* #param {Dom Element} div El Elemento dom en donde se pinta el ninepath
* #param {function} callback La funcion que se llamara cuando se termina
* la carga de la imagen y el pintado del elemento div.
* #returns {NinePatch} Un objeto nine path
*/
function NinePatch(div,callback)
{
this.div = div;
this.callback =callback;
this.padding = {top:0,left:0,right:0,bottom:0};
// Load 9patch from background-image
this.bgImage = new Image();
this.bgImage.src = NinePatchGetStyle(this.div, 'background-image').replace(/"/g, "").replace(/url\(|\)$/ig, "");
var este = this;
this.bgImage.onload = function()
{
este.originalBgColor = NinePatchGetStyle(este.div, 'background-color');
este.div.style.background = 'none';
// Create a temporary canvas to get the 9Patch index data.
var tempCtx, tempCanvas;
tempCanvas = document.createElement('canvas');
tempCanvas.width = este.bgImage.width;
tempCanvas.height = este.bgImage.height;
tempCtx = tempCanvas.getContext('2d');
tempCtx.drawImage(este.bgImage, 0, 0);
// Obteniendo el padding lateral derecho
var dataPad = tempCtx.getImageData(este.bgImage.width-1,0,1,este.bgImage.height).data;
var padRight = este.getPadBorder(dataPad,este.bgImage.width,este.bgImage.height);
este.padding.top = padRight.top;
este.padding.bottom = padRight.bottom;
dataPad = tempCtx.getImageData(0,este.bgImage.height-1,este.bgImage.width,1).data;
var padBottom = este.getPadBorder(dataPad,este.bgImage.width,este.bgImage.height);
este.padding.left = padBottom.top;
este.padding.right = padBottom.bottom;
// Loop over each horizontal pixel and get piece
var data = tempCtx.getImageData(0, 0, este.bgImage.width, 1).data;
// Use the upper-left corner to get staticColor, use the upper-right corner
// to get the repeatColor.
var tempLength = data.length - 4;
var staticColor = data[0] + ',' + data[1] + ',' + data[2] + ',' + data[3];
var repeatColor = data[tempLength] + ',' + data[tempLength + 1] + ',' +
data[tempLength + 2] + ',' + data[tempLength + 3];
este.horizontalPieces = este.getPieces(data, staticColor, repeatColor);
// Loop over each horizontal pixel and get piece
data = tempCtx.getImageData(0, 0, 1, este.bgImage.height).data;
este.verticalPieces = este.getPieces(data, staticColor, repeatColor);
// use this.horizontalPieces and this.verticalPieces to generate image
este.draw();
este.div.onresize = function()
{
este.draw();
};
if(callback !== undefined)
{
if (typeof(callback) === "function")
callback();
}
};
}
// Stores the HTMLDivElement that's using the 9patch image
NinePatch.prototype.div = null;
// Padding
NinePatch.prototype.padding = null;
// Get padding
NinePatch.prototype.callback = null;
// Stores the original background css color to use later
NinePatch.prototype.originalBG = null;
// Stores the pieces used to generate the horizontal layout
NinePatch.prototype.horizontalPieces = null;
// Stores the pieces used to generate the vertical layout
NinePatch.prototype.verticalPieces = null;
// Stores the 9patch image
NinePatch.prototype.bgImage = null;
// Gets the horizontal|vertical pieces based on image data
NinePatch.prototype.getPieces = function(data, staticColor, repeatColor)
{
var tempDS, tempPosition, tempWidth, tempColor, tempType;
var tempArray = new Array();
tempColor = data[4] + ',' + data[5] + ',' + data[6] + ',' + data[7];
tempDS = (tempColor === staticColor ? 's' : (tempColor === repeatColor ? 'r' : 'd'));
tempPosition = 1;
for (var i = 4, n = data.length - 4; i < n; i += 4)
{
tempColor = data[i] + ',' + data[i + 1] + ',' + data[i + 2] + ',' + data[i + 3];
tempType = (tempColor === staticColor ? 's' : (tempColor === repeatColor ? 'r' : 'd'));
if (tempDS !== tempType)
{
// box changed colors
tempWidth = (i / 4) - tempPosition;
tempArray.push(new Array(tempDS, tempPosition, tempWidth));
tempDS = tempType;
tempPosition = i / 4;
tempWidth = 1;
}
}
// push end
tempWidth = (i / 4) - tempPosition;
tempArray.push(new Array(tempDS, tempPosition, tempWidth));
return tempArray;
};
NinePatch.prototype.getPadBorder = function(dataPad,width,height)
{
var staticRight = dataPad[0] + ',' + dataPad[1] + ',' + dataPad[2] + ',' + dataPad[3];
var pad={top:0,bottom:0};
// Padding para la parte superior
for (var i=0;i<dataPad.length;i+=4)
{
var tempColor = dataPad[i] + ',' + dataPad[i + 1] + ',' + dataPad[i + 2] + ',' + dataPad[i + 3];
if(tempColor !==staticRight)
break;
pad.top++;
}
// padding inferior
for (var i=dataPad.length-4;i>=0;i-=4)
{
var tempColor = dataPad[i] + ',' + dataPad[i + 1] + ',' + dataPad[i + 2] + ',' + dataPad[i + 3];
if(tempColor !==staticRight)
break;
pad.bottom++;
}
return pad;
};
// Function to draw the background for the given element size.
NinePatch.prototype.draw = function()
{
var dCtx, dCanvas, dWidth, dHeight;
if(this.horizontalPieces === null)
return;
dWidth = this.div.offsetWidth;
dHeight = this.div.offsetHeight;
dCanvas = document.createElement('canvas');
dCtx = dCanvas.getContext('2d');
dCanvas.width = dWidth;
dCanvas.height = dHeight;
var fillWidth, fillHeight;
// Determine the width for the static and dynamic pieces
var tempStaticWidth = 0;
var tempDynamicCount = 0;
for (var i = 0, n = this.horizontalPieces.length; i < n; i++)
{
if (this.horizontalPieces[i][0] === 's')
tempStaticWidth += this.horizontalPieces[i][2];
else
tempDynamicCount++;
}
fillWidth = (dWidth - tempStaticWidth) / tempDynamicCount;
// Determine the height for the static and dynamic pieces
var tempStaticHeight = 0;
tempDynamicCount = 0;
for (var i = 0, n = this.verticalPieces.length; i < n; i++)
{
if (this.verticalPieces[i][0] === 's')
tempStaticHeight += this.verticalPieces[i][2];
else
tempDynamicCount++;
}
fillHeight = (dHeight - tempStaticHeight) / tempDynamicCount;
// Loop through each of the vertical/horizontal pieces and draw on
// the canvas
for (var i = 0, m = this.verticalPieces.length; i < m; i++)
{
for (var j = 0, n = this.horizontalPieces.length; j < n; j++)
{
var tempFillWidth, tempFillHeight;
tempFillWidth = (this.horizontalPieces[j][0] === 'd') ?
fillWidth : this.horizontalPieces[j][2];
tempFillHeight = (this.verticalPieces[i][0] === 'd') ?
fillHeight : this.verticalPieces[i][2];
// Stretching :
if (this.verticalPieces[i][0] !== 'r') {
// Stretching is the same function for the static squares
// the only difference is the widths/heights are the same.
dCtx.drawImage(
this.bgImage,
this.horizontalPieces[j][1], this.verticalPieces[i][1],
this.horizontalPieces[j][2], this.verticalPieces[i][2],
0, 0,
tempFillWidth, tempFillHeight);
} else {
var tempCanvas = document.createElement('canvas');
tempCanvas.width = this.horizontalPieces[j][2];
tempCanvas.height = this.verticalPieces[i][2];
var tempCtx = tempCanvas.getContext('2d');
tempCtx.drawImage(this.bgImage,
this.horizontalPieces[j][1], this.verticalPieces[i][1],
this.horizontalPieces[j][2], this.verticalPieces[i][2],
0, 0,
this.horizontalPieces[j][2], this.verticalPieces[i][2]);
var tempPattern = dCtx.createPattern(tempCanvas, 'repeat');
dCtx.fillStyle = tempPattern;
dCtx.fillRect(
0, 0,
tempFillWidth, tempFillHeight);
}
// Shift to next x position
dCtx.translate(tempFillWidth, 0);
}
// shift back to 0 x and down to the next line
dCtx.translate(-dWidth, (this.verticalPieces[i][0] === 's' ? this.verticalPieces[i][2] : fillHeight));
}
// store the canvas as the div's background
var url = dCanvas.toDataURL("image/png");
var tempIMG = new Image();
var _this = this;
tempIMG.onload = function(event)
{
_this.div.style.background = _this.originalBgColor + " url(" + url + ") no-repeat";
};
tempIMG.src = url;
};
The usage is the following:
var elemDom = document.getElementById("idDiv");
var background = "border.9.png";
if (background.match(/\.9\.(png|gif)/i)) // Es nine path?
{
elemDom.style.backgroundRepeat = "no-repeat";
elemDom.style.backgroundPosition = "-1000px -1000px";
elemDom.style.backgroundImage = "url('"+background+"')";
var ninePatch = new NinePatch(elemDom,function()
{
elemDom.style.paddingLeft = ninePatch.padding.left;
elemDom.style.paddingTop = ninePatch.padding.top;
elemDom.style.paddingRight = ninePatch.padding.right;
elemDom.style.paddingBottom = ninePatch.padding.bottom;
});
}

Answer 4

I forked https://github.com/chrislondon/9-Patch-Image-for-Websites and fixed the bugs based on the above comments. Now the 9-Patch javascript works well. Please check out https://github.com/blackmonkey/jQuery-9-Patch