// IE5.5+ PNG Alpha Fix v2.0 Alpha: Background Tiling Support // (c) 2008 Angus Turnbull http://www.twinhelix.com // This is licensed under the GNU LGPL, version 2.1 or later. // For details, see: http://creativecommons.org/licenses/LGPL/2.1/ var IEPNGFix = window.IEPNGFix || {}; IEPNGFix.tileBG = function(elm, pngSrc, ready) { // Params: A reference to a DOM element, the PNG src file pathname, and a // hidden "ready-to-run" passed when called back after image preloading. var data = this.data[elm.uniqueID], elmW = Math.max(elm.clientWidth, elm.scrollWidth), elmH = Math.max(elm.clientHeight, elm.scrollHeight), bgX = elm.currentStyle.backgroundPositionX, bgY = elm.currentStyle.backgroundPositionY, bgR = elm.currentStyle.backgroundRepeat; // Cache of DIVs created per element, and image preloader/data. if (!data.tiles) { data.tiles = { elm: elm, src: '', cache: [], img: new Image(), old: {} }; } var tiles = data.tiles, pngW = tiles.img.width, pngH = tiles.img.height; if (pngSrc) { if (!ready && pngSrc != tiles.src) { // New image? Preload it with a callback to detect dimensions. tiles.img.onload = function() { this.onload = null; IEPNGFix.tileBG(elm, pngSrc, 1); }; return tiles.img.src = pngSrc; } } else { // No image? if (tiles.src) ready = 1; pngW = pngH = 0; } tiles.src = pngSrc; if (!ready && elmW == tiles.old.w && elmH == tiles.old.h && bgX == tiles.old.x && bgY == tiles.old.y && bgR == tiles.old.r) { return; } // Convert English and percentage positions to pixels. var pos = { top: '0%', left: '0%', center: '50%', bottom: '100%', right: '100%' }, x, y, pc; x = pos[bgX] || bgX; y = pos[bgY] || bgY; if (pc = x.match(/(\d+)%/)) { x = Math.round((elmW - pngW) * (parseInt(pc[1]) / 100)); } if (pc = y.match(/(\d+)%/)) { y = Math.round((elmH - pngH) * (parseInt(pc[1]) / 100)); } x = parseInt(x); y = parseInt(y); // Handle backgroundRepeat. var repeatX = { 'repeat': 1, 'repeat-x': 1 }[bgR], repeatY = { 'repeat': 1, 'repeat-y': 1 }[bgR]; if (repeatX) { x %= pngW; if (x > 0) x -= pngW; } if (repeatY) { y %= pngH; if (y > 0) y -= pngH; } // Go! this.hook.enabled = 0; if (!({ relative: 1, absolute: 1 }[elm.currentStyle.position])) { elm.style.position = 'relative'; } var count = 0, xPos, maxX = repeatX ? elmW : x + 0.1, yPos, maxY = repeatY ? elmH : y + 0.1, d, s, isNew; if (pngW && pngH) { for (xPos = x; xPos < maxX; xPos += pngW) { for (yPos = y; yPos < maxY; yPos += pngH) { isNew = 0; if (!tiles.cache[count]) { tiles.cache[count] = document.createElement('div'); isNew = 1; } var clipR = (xPos + pngW > elmW ? elmW - xPos : pngW), clipB = (yPos + pngH > elmH ? elmH - yPos : pngH); d = tiles.cache[count]; s = d.style; s.behavior = 'none'; s.left = xPos + 'px'; s.top = yPos + 'px'; s.width = clipR + 'px'; s.height = clipB + 'px'; s.clip = 'rect(' + (yPos < 0 ? 0 - yPos : 0) + 'px,' + clipR + 'px,' + clipB + 'px,' + (xPos < 0 ? 0 - xPos : 0) + 'px)'; s.display = 'block'; if (isNew) { s.position = 'absolute'; s.zIndex = -999; if (elm.firstChild) { elm.insertBefore(d, elm.firstChild); } else { elm.appendChild(d); } } this.fix(d, pngSrc, 0); count++; } } } while (count < tiles.cache.length) { this.fix(tiles.cache[count], '', 0); tiles.cache[count++].style.display = 'none'; } this.hook.enabled = 1; // Cache so updates are infrequent. tiles.old = { w: elmW, h: elmH, x: bgX, y: bgY, r: bgR }; }; IEPNGFix.update = function() { // Update all PNG backgrounds. for (var i in IEPNGFix.data) { var t = IEPNGFix.data[i].tiles; if (t && t.elm && t.src) { IEPNGFix.tileBG(t.elm, t.src); } } }; IEPNGFix.update.timer = 0; if (window.attachEvent && !window.opera) { window.attachEvent('onresize', function() { clearTimeout(IEPNGFix.update.timer); IEPNGFix.update.timer = setTimeout(IEPNGFix.update, 100); }); }