Adobe® Flex® 4 Language Reference
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flash.text 
TextLineMetrics 
Packageflash.text
Classpublic class TextLineMetrics
InheritanceTextLineMetrics Inheritance Object

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The TextLineMetrics class contains information about the text position and measurements of a line of text within a text field. All measurements are in pixels. Objects of this class are returned by the flash.text.TextField.getLineMetrics() method.

For measurements related to the text field containing the line of text (for example, the "Text Field height" measurement in the diagram), see flash.text.TextField.

The following diagram indicates the points and measurements of a text field and the line of text the field contains:

An image illustrating text metrics

View the examples

See also



Public Properties
 PropertyDefined By
  ascent : Number
The ascent value of the text is the length from the baseline to the top of the line height in pixels.
TextLineMetrics
 Inheritedconstructor : Object
A reference to the class object or constructor function for a given object instance.
Object
  descent : Number
The descent value of the text is the length from the baseline to the bottom depth of the line in pixels.
TextLineMetrics
  height : Number
The height value of the text of the selected lines (not necessarily the complete text) in pixels.
TextLineMetrics
  leading : Number
The leading value is the measurement of the vertical distance between the lines of text.
TextLineMetrics
 Inheritedprototype : Object
[static] A reference to the prototype object of a class or function object.
Object
  width : Number
The width value is the width of the text of the selected lines (not necessarily the complete text) in pixels.
TextLineMetrics
  x : Number
The x value is the left position of the first character in pixels.
TextLineMetrics
Public Methods
 MethodDefined By
  
TextLineMetrics(x:Number, width:Number, height:Number, ascent:Number, descent:Number, leading:Number)
Creates a TextLineMetrics object.
TextLineMetrics
 Inherited
Indicates whether an object has a specified property defined.
Object
 Inherited
Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.
Object
 Inherited
Indicates whether the specified property exists and is enumerable.
Object
 Inherited
Sets the availability of a dynamic property for loop operations.
Object
 Inherited
Returns the string representation of this object, formatted according to locale-specific conventions.
Object
 Inherited
Returns the string representation of the specified object.
Object
 Inherited
Returns the primitive value of the specified object.
Object
Property Detail

ascent

property
public var ascent:Number

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The ascent value of the text is the length from the baseline to the top of the line height in pixels. See the "Ascent" measurement in the overview diagram for this class.

See also

descent

property 
public var descent:Number

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The descent value of the text is the length from the baseline to the bottom depth of the line in pixels. See the "Descent" measurement in the overview diagram for this class.

See also

height

property 
public var height:Number

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The height value of the text of the selected lines (not necessarily the complete text) in pixels. The height of the text line does not include the gutter height. See the "Line height" measurement in the overview diagram for this class.

See also

leading

property 
public var leading:Number

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The leading value is the measurement of the vertical distance between the lines of text. See the "Leading" measurement in the overview diagram for this class.

See also

width

property 
public var width:Number

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The width value is the width of the text of the selected lines (not necessarily the complete text) in pixels. The width of the text line is not the same as the width of the text field. The width of the text line is relative to the text field width, minus the gutter width of 4 pixels (2 pixels on each side). See the "Text Line width" measurement in the overview diagram for this class.

See also

x

property 
public var x:Number

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

The x value is the left position of the first character in pixels. This value includes the margin, indent (if any), and gutter widths. See the "Text Line x-position" in the overview diagram for this class.

See also

Constructor Detail

TextLineMetrics

()Constructor
public function TextLineMetrics(x:Number, width:Number, height:Number, ascent:Number, descent:Number, leading:Number)

Language Version: ActionScript 3.0
Runtime Versions: AIR 1.0 Flash Player 9, Flash Lite 4

Creates a TextLineMetrics object. The TextLineMetrics object contains information about the text metrics of a line of text in a text field. Objects of this class are returned by the flash.text.TextField.getLineMetrics() method.

See the diagram in the overview for this class for the properties in context.

Parameters
x:Number — The left position of the first character in pixels.
 
width:Number — The width of the text of the selected lines (not necessarily the complete text) in pixels.
 
height:Number — The height of the text of the selected lines (not necessarily the complete text) in pixels.
 
ascent:Number — The length from the baseline to the top of the line height in pixels.
 
descent:Number — The length from the baseline to the bottom depth of the line in pixels.
 
leading:Number — The measurement of the vertical distance between the lines of text.

See also

TextLineMetricsExample.as

The following example creates the classes TextLineMetricsExample and LineMetricsReader to print out a message in the Flash Player via an XML object. This is accomplished using the following steps:
  1. Create a property called label of type TextField.
  2. The constructor calls configureAssets(), which does the following:
    • Sets the stage's alignment to top-left and no scale.
    • Creates a new TextField object named label.
    • Enables label's background and sets the color to white.
    • Allows label's text to span multiple lines with automatic word wrapping.
    • Assigns the result of a call to getLabelText() to the text property of label. The getLabelText() method creates a variable of type XML and assigns it to an XML node named body, which is populated with a long sentence.
    • Adds label to the display list using addChild().
  3. A method that listens for resize events performed on the stage is then added called resizeHandler(). Every time the Flash Player window size is changed, a RESIZE event is dispatched and the following happens:
    • draw() is called to ensure that label appears in the center of the stage and surrounded by a 10-pixel buffer.
    • setTimeout() then executes showMetrics() after a short delay. The delay is added because the line metrics are not updated until after the RESIZE event has completed and the stage has fully re-drawn.
    • showMetrics() assigns a TextLineMetrics variable named metrics to the result of a call to getLineMetrics() and this variable is then passed to a new instance of a LineMetricsReader instance named reader. The two variables are then used within calls to trace() to print out the first (and only) line of label and information provided by the LineMetricsReader instance through its toString() method.
  4. The constructor forces a single dispatch of the resize event to force label to be drawn correctly when the SWF file is first loaded.
package {
    import flash.display.Sprite;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.events.*;
    import flash.text.TextField;
    import flash.text.TextLineMetrics;
    import flash.utils.setTimeout;

    public class TextLineMetricsExample extends Sprite {
        private var gutter:int = 10;
        private var label:TextField;

        public function TextLineMetricsExample() {
            configureAssets();
            configureListeners();
            resizeHandler(new Event(Event.RESIZE));
        }

        private function showMetrics():void {
            var metrics:TextLineMetrics = label.getLineMetrics(0);
            var reader:LineMetricsReader = new LineMetricsReader(metrics);
            trace("lineText: " + label.getLineText(0));
            trace("metrics: " + reader);
        }

        private function configureAssets():void {
            stage.align = StageAlign.TOP_LEFT;
            stage.scaleMode = StageScaleMode.NO_SCALE;

            label = new TextField();
            label.background = true;
            label.backgroundColor = 0xFFFFFF;
            label.multiline = true;
            label.wordWrap = true;
            label.text = getLabelText();
            addChild(label);
        }

        private function configureListeners():void {
            stage.addEventListener(Event.RESIZE, resizeHandler);
        }

        private function resizeHandler(event:Event):void {
            draw();
            setTimeout(showMetrics, 100);
        }

        private function draw():void {
            label.x = gutter;
            label.y = gutter;
            label.width = stage.stageWidth - (gutter * 2);
            label.height = stage.stageHeight - (gutter * 2);
        }

        private function getLabelText():String {
            var text:XML = <body>The Flex product line enables developers to build rich Internet applications that blend the responsiveness of desktop software, the cross-platform reach of the web, and the expressiveness of the Flash Platform.</body>
            return text.toString();
        }
    }
}

import flash.text.TextLineMetrics;

class LineMetricsReader {
    private var metrics:TextLineMetrics;

    public function LineMetricsReader(metrics:TextLineMetrics) {
        this.metrics = metrics;
    }

    public function toString():String {
        return "[TextLineMetrics ascent:" + metrics.ascent
            + ", descent:" + metrics.descent
            + ", leading:" + metrics.leading
            + ", width:" + metrics.width
            + ", height:" + metrics.height
            + ", x:" + metrics.x
            + "]";
    }
}