forked from lojjic/PIE
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BackgroundRenderer.js
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BackgroundRenderer.js
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/**
* Renderer for element backgrounds.
* @constructor
* @param {Element} el The target element
* @param {Object} styleInfos The StyleInfo objects
* @param {PIE.RootRenderer} parent
*/
PIE.BackgroundRenderer = PIE.RendererBase.newRenderer( {
boxZIndex: 2,
boxName: 'background',
needsUpdate: function() {
var si = this.styleInfos;
return si.backgroundInfo.changed() || si.borderRadiusInfo.changed();
},
isActive: function() {
var si = this.styleInfos;
return si.borderImageInfo.isActive() ||
si.borderRadiusInfo.isActive() ||
si.backgroundInfo.isActive() ||
( si.boxShadowInfo.isActive() && si.boxShadowInfo.getProps().inset );
},
/**
* Draw the shapes
*/
draw: function() {
var bounds = this.boundsInfo.getBounds();
if( bounds.w && bounds.h ) {
this.drawBgColor();
this.drawBgImages();
}
},
/**
* Draw the background color shape
*/
drawBgColor: function() {
var props = this.styleInfos.backgroundInfo.getProps(),
bounds = this.boundsInfo.getBounds(),
el = this.targetElement,
color = props && props.color,
shape, w, h, s, alpha;
if( color && color.alpha() > 0 ) {
this.hideBackground();
shape = this.getShape( 'bgColor', 'fill', this.getBox(), 1 );
w = bounds.w;
h = bounds.h;
shape.stroked = false;
shape.coordsize = w * 2 + ',' + h * 2;
shape.coordorigin = '1,1';
shape.path = this.getBoxPath( null, 2 );
s = shape.style;
s.width = w;
s.height = h;
shape.fill.color = color.colorValue( el );
alpha = color.alpha();
if( alpha < 1 ) {
shape.fill.opacity = alpha;
}
} else {
this.deleteShape( 'bgColor' );
}
},
/**
* Draw all the background image layers
*/
drawBgImages: function() {
var props = this.styleInfos.backgroundInfo.getProps(),
bounds = this.boundsInfo.getBounds(),
images = props && props.bgImages,
img, shape, w, h, s, i;
if( images ) {
this.hideBackground();
w = bounds.w;
h = bounds.h;
i = images.length;
while( i-- ) {
img = images[i];
shape = this.getShape( 'bgImage' + i, 'fill', this.getBox(), 2 );
shape.stroked = false;
shape.fill.type = 'tile';
shape.fillcolor = 'none';
shape.coordsize = w * 2 + ',' + h * 2;
shape.coordorigin = '1,1';
shape.path = this.getBoxPath( 0, 2 );
s = shape.style;
s.width = w;
s.height = h;
if( img.imgType === 'linear-gradient' ) {
this.addLinearGradient( shape, img );
}
else {
shape.fill.src = img.imgUrl;
this.positionBgImage( shape, i );
}
}
}
// Delete any bgImage shapes previously created which weren't used above
i = images ? images.length : 0;
while( this.deleteShape( 'bgImage' + i++ ) ) {}
},
/**
* Set the position and clipping of the background image for a layer
* @param {Element} shape
* @param {number} index
*/
positionBgImage: function( shape, index ) {
var me = this;
PIE.Util.withImageSize( shape.fill.src, function( imgSize ) {
var el = me.targetElement,
bounds = me.boundsInfo.getBounds(),
elW = bounds.w,
elH = bounds.h;
// It's possible that the element dimensions are zero now but weren't when the original
// update executed, make sure that's not the case to avoid divide-by-zero error
if( elW && elH ) {
var fill = shape.fill,
bgInfo = me.styleInfos.backgroundInfo,
bg = bgInfo.getProps().bgImages[ index ],
bgAreaSize = bgInfo.getBgAreaSize( bg.bgOrigin, me.boundsInfo, me.styleInfos.borderInfo ),
adjustedImgSize = ( bg.bgSize || PIE.BgSize.DEFAULT ).pixels(
me.targetElement, bgAreaSize.w, bgAreaSize.h, imgSize.w, imgSize.h
),
bgOriginXY = me.getBgOriginXY( bg.bgOrigin ),
bgPos = bg.bgPosition ? bg.bgPosition.coords( el, bgAreaSize.w - adjustedImgSize.w, bgAreaSize.h - adjustedImgSize.h ) : { x:0, y:0 },
repeat = bg.imgRepeat,
pxX, pxY,
clipT = 0, clipL = 0,
clipR = elW + 1, clipB = elH + 1, //make sure the default clip region is not inside the box (by a subpixel)
clipAdjust = PIE.ieVersion === 8 ? 0 : 1; //prior to IE8 requires 1 extra pixel in the image clip region
// Positioning - find the pixel offset from the top/left and convert to a ratio
// The position is shifted by half a pixel, to adjust for the half-pixel coordorigin shift which is
// needed to fix antialiasing but makes the bg image fuzzy.
pxX = Math.round( bgOriginXY.x + bgPos.x ) + 0.5;
pxY = Math.round( bgOriginXY.y + bgPos.y ) + 0.5;
fill.position = ( pxX / elW ) + ',' + ( pxY / elH );
// Set the size of the image. We have to actually set it to px values otherwise it will not honor
// the user's browser zoom level and always display at its natural screen size.
fill['size']['x'] = 1; //Can be any value, just has to be set to "prime" it so the next line works. Weird!
fill['size'] = adjustedImgSize.w + 'px,' + adjustedImgSize.h + 'px';
// Repeating - clip the image shape
if( repeat && repeat !== 'repeat' ) {
if( repeat === 'repeat-x' || repeat === 'no-repeat' ) {
clipT = pxY + 1;
clipB = pxY + adjustedImgSize.h + clipAdjust;
}
if( repeat === 'repeat-y' || repeat === 'no-repeat' ) {
clipL = pxX + 1;
clipR = pxX + adjustedImgSize.w + clipAdjust;
}
shape.style.clip = 'rect(' + clipT + 'px,' + clipR + 'px,' + clipB + 'px,' + clipL + 'px)';
}
}
} );
},
/**
* For a given background-origin value, return the x/y position of the origin
* from the top-left of the element bounds.
* @param {String} bgOrigin
*/
getBgOriginXY: function( bgOrigin ) {
var me = this,
el = me.targetElement,
x = 0,
y = 0,
borders, getLength, cs;
if( bgOrigin !== 'border-box' ) {
borders = me.styleInfos.borderInfo.getProps();
if( borders && ( borders = borders.widths ) ) {
x += borders[ 'l' ].pixels( el );
y += borders[ 't' ].pixels( el );
}
}
if ( bgOrigin === 'content-box' ) {
getLength = PIE.getLength;
cs = el.currentStyle;
x += getLength( cs.paddingLeft ).pixels( el );
y += getLength( cs.paddingTop ).pixels( el );
}
return { x: x, y: y };
},
/**
* Draw the linear gradient for a gradient layer
* @param {Element} shape
* @param {Object} info The object holding the information about the gradient
*/
addLinearGradient: function( shape, info ) {
var el = this.targetElement,
bounds = this.boundsInfo.getBounds(),
w = bounds.w,
h = bounds.h,
fill = shape.fill,
stops = info.stops,
stopCount = stops.length,
PI = Math.PI,
GradientUtil = PIE.GradientUtil,
perpendicularIntersect = GradientUtil.perpendicularIntersect,
distance = GradientUtil.distance,
metrics = GradientUtil.getGradientMetrics( el, w, h, info ),
angle = metrics.angle,
startX = metrics.startX,
startY = metrics.startY,
startCornerX = metrics.startCornerX,
startCornerY = metrics.startCornerY,
endCornerX = metrics.endCornerX,
endCornerY = metrics.endCornerY,
deltaX = metrics.deltaX,
deltaY = metrics.deltaY,
lineLength = metrics.lineLength,
vmlAngle, vmlGradientLength, vmlColors,
stopPx, vmlOffsetPct,
p, i, j, before, after;
// In VML land, the angle of the rendered gradient depends on the aspect ratio of the shape's
// bounding box; for example specifying a 45 deg angle actually results in a gradient
// drawn diagonally from one corner to its opposite corner, which will only appear to the
// viewer as 45 degrees if the shape is equilateral. We adjust for this by taking the x/y deltas
// between the start and end points, multiply one of them by the shape's aspect ratio,
// and get their arctangent, resulting in an appropriate VML angle. If the angle is perfectly
// horizontal or vertical then we don't need to do this conversion.
vmlAngle = ( angle % 90 ) ? Math.atan2( deltaX * w / h, deltaY ) / PI * 180 : ( angle + 90 );
// VML angles are 180 degrees offset from CSS angles
vmlAngle += 180;
vmlAngle = vmlAngle % 360;
// Add all the stops to the VML 'colors' list, including the first and last stops.
// For each, we find its pixel offset along the gradient-line; if the offset of a stop is less
// than that of its predecessor we increase it to be equal. We then map that pixel offset to a
// percentage along the VML gradient-line, which runs from shape corner to corner.
p = perpendicularIntersect( startCornerX, startCornerY, angle, endCornerX, endCornerY );
vmlGradientLength = distance( startCornerX, startCornerY, p[0], p[1] );
vmlColors = [];
p = perpendicularIntersect( startX, startY, angle, startCornerX, startCornerY );
vmlOffsetPct = distance( startX, startY, p[0], p[1] ) / vmlGradientLength * 100;
// Find the pixel offsets along the CSS3 gradient-line for each stop.
stopPx = [];
for( i = 0; i < stopCount; i++ ) {
stopPx.push( stops[i].offset ? stops[i].offset.pixels( el, lineLength ) :
i === 0 ? 0 : i === stopCount - 1 ? lineLength : null );
}
// Fill in gaps with evenly-spaced offsets
for( i = 1; i < stopCount; i++ ) {
if( stopPx[ i ] === null ) {
before = stopPx[ i - 1 ];
j = i;
do {
after = stopPx[ ++j ];
} while( after === null );
stopPx[ i ] = before + ( after - before ) / ( j - i + 1 );
}
// Make sure each stop's offset is no less than the one before it
stopPx[ i ] = Math.max( stopPx[ i ], stopPx[ i - 1 ] );
}
// Convert to percentage along the VML gradient line and add to the VML 'colors' value
for( i = 0; i < stopCount; i++ ) {
vmlColors.push(
( vmlOffsetPct + ( stopPx[ i ] / vmlGradientLength * 100 ) ) + '% ' + stops[i].color.colorValue( el )
);
}
// Now, finally, we're ready to render the gradient fill. Set the start and end colors to
// the first and last stop colors; this just sets outer bounds for the gradient.
fill['angle'] = vmlAngle;
fill['type'] = 'gradient';
fill['method'] = 'sigma';
fill['color'] = stops[0].color.colorValue( el );
fill['color2'] = stops[stopCount - 1].color.colorValue( el );
if( fill['colors'] ) { //sometimes the colors object isn't initialized so we have to assign it directly (?)
fill['colors'].value = vmlColors.join( ',' );
} else {
fill['colors'] = vmlColors.join( ',' );
}
},
/**
* Hide the actual background image and color of the element.
*/
hideBackground: function() {
var rs = this.targetElement.runtimeStyle;
rs.backgroundImage = 'url(about:blank)'; //ensures the background area reacts to mouse events
rs.backgroundColor = 'transparent';
},
destroy: function() {
PIE.RendererBase.destroy.call( this );
var rs = this.targetElement.runtimeStyle;
rs.backgroundImage = rs.backgroundColor = '';
}
} );