CSS: Support relative adjustment in any applicable unit

Fixes gh-1711
Closes gh-2011

(cherry picked from commit 9b03f6df88a8d9dbda3f7893cdd84e3a3c70da17)

Conflicts:
	src/css.js
	src/effects.js

src/css.js

@@ -3,10 +3,12 @@ define([
 	"./var/pnum",
 	"./core/access",
 	"./css/var/rmargin",
+	"./var/rcssNum",
 	"./css/var/rnumnonpx",
 	"./css/var/cssExpand",
 	"./css/var/isHidden",
 	"./css/curCSS",
+	"./css/adjustCSS",
 	"./css/defaultDisplay",
 	"./css/addGetHookIf",
 	"./css/support",
@@ -15,8 +17,8 @@ define([
 	"./css/swap",
 	"./core/ready",
 	"./selector" // contains
-], function( jQuery, pnum, access, rmargin, rnumnonpx, cssExpand, isHidden,
-	curCSS, defaultDisplay, addGetHookIf, support ) {
+], function( jQuery, pnum, access, rmargin, rcssNum, rnumnonpx, cssExpand, isHidden,
+	curCSS, adjustCSS, defaultDisplay, addGetHookIf, support ) {
 
 var
 	// BuildExclude
@@ -30,7 +32,6 @@ var
 	// https://developer.mozilla.org/en-US/docs/CSS/display
 	rdisplayswap = /^(none|table(?!-c[ea]).+)/,
 	rnumsplit = new RegExp( "^(" + pnum + ")(.*)$", "i" ),
-	rrelNum = new RegExp( "^([+-])=(" + pnum + ")", "i" ),
 
 	cssShow = { position: "absolute", visibility: "hidden", display: "block" },
 	cssNormalTransform = {
@@ -273,9 +274,9 @@ jQuery.extend({
 		if ( value !== undefined ) {
 			type = typeof value;
 
-			// convert relative number strings (+= or -=) to relative numbers. #7345
-			if ( type === "string" && (ret = rrelNum.exec( value )) ) {
-				value = ( ret[1] + 1 ) * ret[2] + parseFloat( jQuery.css( elem, name ) );
+			// Convert "+=" or "-=" to relative numbers (#7345)
+			if ( type === "string" && (ret = rcssNum.exec( value )) && ret[ 1 ] ) {
+				value = adjustCSS( elem, name, ret );
 				// Fixes bug #9237
 				type = "number";
 			}
@@ -285,9 +286,9 @@ jQuery.extend({
 				return;
 			}
 
-			// If a number was passed in, add 'px' (except for certain CSS properties)
-			if ( type === "number" && !jQuery.cssNumber[ origName ] ) {
-				value += "px";
+			// If a number was passed in, add the unit (except for certain CSS properties)
+			if ( type === "number" ) {
+				value += ret && ret[ 3 ] || ( jQuery.cssNumber[ origName ] ? "" : "px" );
 			}
 
 			// Fixes #8908, it can be done more correctly by specifing setters in cssHooks,

src/css/adjustCSS.js

+define([
+	"../core",
+	"../var/rcssNum"
+], function( jQuery, rcssNum ) {
+
+function adjustCSS( elem, prop, valueParts, tween ) {
+	var adjusted,
+		scale = 1,
+		maxIterations = 20,
+		currentValue = tween ?
+			function() { return tween.cur(); } :
+			function() { return jQuery.css( elem, prop, "" ); },
+		initial = currentValue(),
+		unit = valueParts && valueParts[ 3 ] || ( jQuery.cssNumber[ prop ] ? "" : "px" ),
+		// Starting value computation is required for potential unit mismatches
+		initialInUnit = ( jQuery.cssNumber[ prop ] || unit !== "px" && +initial ) &&
+			rcssNum.exec( jQuery.css( elem, prop ) );
+
+	if ( initialInUnit && initialInUnit[ 3 ] !== unit ) {
+		// Trust units reported by jQuery.css
+		unit = unit || initialInUnit[ 3 ];
+
+		// Make sure we update the tween properties later on
+		valueParts = valueParts || [];
+
+		// Iteratively approximate from a nonzero starting point
+		initialInUnit = +initial || 1;
+
+		do {
+			// If previous iteration zeroed out, double until we get *something*.
+			// Use string for doubling so we don't accidentally see scale as unchanged below
+			scale = scale || ".5";
+
+			// Adjust and apply
+			initialInUnit = initialInUnit / scale;
+			jQuery.style( elem, prop, initialInUnit + unit );
+
+		// Update scale, tolerating zero or NaN from tween.cur()
+		// Break the loop if scale is unchanged or perfect, or if we've just had enough.
+		} while (
+			scale !== (scale = currentValue() / initial) && scale !== 1 && --maxIterations
+		);
+	}
+
+	if ( valueParts ) {
+		initialInUnit = +initialInUnit || +initial || 0;
+		// Apply relative offset (+=/-=) if specified
+		adjusted = valueParts[ 1 ] ?
+			initialInUnit + ( valueParts[ 1 ] + 1 ) * valueParts[ 2 ] :
+			+valueParts[ 2 ];
+		if ( tween ) {
+			tween.unit = unit;
+			tween.start = initialInUnit;
+			tween.end = adjusted;
+		}
+	}
+	return adjusted;
+}
+
+return adjustCSS;
+});

src/effects.js

 define([
 	"./core",
-	"./var/pnum",
+	"./var/rcssNum",
 	"./css/var/cssExpand",
 	"./css/var/isHidden",
+	"./css/adjustCSS",
 	"./css/defaultDisplay",
 
 	"./core/init",
@@ -11,65 +12,17 @@ define([
 	"./css",
 	"./deferred",
 	"./traversing"
-], function( jQuery, pnum, cssExpand, isHidden, defaultDisplay ) {
+], function( jQuery, rcssNum, cssExpand, isHidden, adjustCSS, defaultDisplay ) {
 
 var
 	fxNow, timerId,
 	rfxtypes = /^(?:toggle|show|hide)$/,
-	rfxnum = new RegExp( "^(?:([+-])=|)(" + pnum + ")([a-z%]*)$", "i" ),
 	rrun = /queueHooks$/,
 	animationPrefilters = [ defaultPrefilter ],
 	tweeners = {
 		"*": [ function( prop, value ) {
-			var tween = this.createTween( prop, value ),
-				target = tween.cur(),
-				parts = rfxnum.exec( value ),
-				unit = parts && parts[ 3 ] || ( jQuery.cssNumber[ prop ] ? "" : "px" ),
-
-				// Starting value computation is required for potential unit mismatches
-				start = ( jQuery.cssNumber[ prop ] || unit !== "px" && +target ) &&
-					rfxnum.exec( jQuery.css( tween.elem, prop ) ),
-				scale = 1,
-				maxIterations = 20;
-
-			if ( start && start[ 3 ] !== unit ) {
-				// Trust units reported by jQuery.css
-				unit = unit || start[ 3 ];
-
-				// Make sure we update the tween properties later on
-				parts = parts || [];
-
-				// Iteratively approximate from a nonzero starting point
-				start = +target || 1;
-
-				do {
-					// If previous iteration zeroed out, double until we get *something*
-					// Use a string for doubling factor so we don't accidentally see scale
-					// as unchanged below
-					scale = scale || ".5";
-
-					// Adjust and apply
-					start = start / scale;
-					jQuery.style( tween.elem, prop, start + unit );
-
-				// Update scale, tolerating zero or NaN from tween.cur()
-				// And breaking the loop if scale is unchanged or perfect,
-				// or if we've just had enough
-				} while (
-					scale !== (scale = tween.cur() / target) && scale !== 1 && --maxIterations
-				);
-			}
-
-			// Update tween properties
-			if ( parts ) {
-				start = tween.start = +start || +target || 0;
-				tween.unit = unit;
-				// If a +=/-= token was provided, we're doing a relative animation
-				tween.end = parts[ 1 ] ?
-					start + ( parts[ 1 ] + 1 ) * parts[ 2 ] :
-					+parts[ 2 ];
-			}
-
+			var tween = this.createTween( prop, value );
+			adjustCSS( tween.elem, prop, rcssNum.exec( value ), tween );
 			return tween;
 		} ]
 	};

src/var/rcssNum.js

+define([
+	"../var/pnum"
+], function( pnum ) {
+
+return new RegExp( "^(?:([+-])=|)(" + pnum + ")([a-z%]*)$", "i" );
+
+});

test/unit/css.js

@@ -217,6 +217,58 @@ test( "css() explicit and relative values", 29, function() {
 	equal( $elem.css("opacity"), "1", "'+=0.5' on opacity (params)" );
 });
 
+test( "css() non-px relative values (gh-1711)", 17, function() {
+	var cssCurrent,
+		units = {},
+		$child = jQuery( "#nothiddendivchild" ),
+		add = function( prop, val, unit ) {
+			var str = ( val < 0 ? "-=" : "+=" ) + Math.abs( val ) + unit;
+			$child.css( prop, str );
+			equal(
+				Math.round( parseFloat( $child.css( prop ) ) ),
+				Math.round( cssCurrent += val * units[ prop ][ unit ] ),
+				prop + ": '" + str + "'"
+			);
+		},
+		getUnits = function( prop ) {
+			units[ prop ] = {
+				"px": 1,
+				"em": parseFloat( $child.css( prop, "100em" ).css( prop ) ) / 100,
+				"pt": parseFloat( $child.css( prop, "100pt" ).css( prop ) ) / 100,
+				"pc": parseFloat( $child.css( prop, "100pc" ).css( prop ) ) / 100,
+				"cm": parseFloat( $child.css( prop, "100cm" ).css( prop ) ) / 100,
+				"mm": parseFloat( $child.css( prop, "100mm" ).css( prop ) ) / 100,
+				"%" : parseFloat( $child.css( prop, "100%"  ).css( prop ) ) / 100
+			};
+		};
+
+	jQuery( "#nothiddendiv" ).css({ height: 1, padding: 0, width: 400 });
+	$child.css({ height: 1, padding: 0 });
+
+	getUnits( "width" );
+	cssCurrent = parseFloat( $child.css( "width", "50%" ).css( "width" ) );
+	add( "width",  25,    "%" );
+	add( "width", -50,    "%" );
+	add( "width",  10,   "em" );
+	add( "width",  10,   "pt" );
+	add( "width",  -2.3, "pt" );
+	add( "width",   5,   "pc" );
+	add( "width",  -5,   "em" );
+	add( "width",  +2,   "cm" );
+	add( "width", -15,   "mm" );
+	add( "width",  21,   "px" );
+
+	getUnits( "lineHeight" );
+	cssCurrent = parseFloat( $child.css( "lineHeight", "1em" ).css( "lineHeight" ) );
+	add( "lineHeight",   2, "em" );
+	add( "lineHeight", -10, "px" );
+	add( "lineHeight",  20, "pt" );
+	add( "lineHeight",  30, "pc" );
+	add( "lineHeight",   1, "cm" );
+	add( "lineHeight", -20, "mm" );
+	add( "lineHeight",  50,  "%" );
+});
+
 test("css(String, Object)", function() {
 	expect( 19 );
 	var j, div, display, ret, success;