TextDelegate
class TextDelegate
| kotlin.Any | |
| ↳ | androidx.ui.text.TextDelegate |
An object that paints text onto a Canvas.
To use a TextDelegate, follow these steps:
- Create an AnnotatedString and pass it to the TextDelegate constructor.
- Call layout to prepare the paragraph.
- Call paint as often as desired to paint the paragraph.
If the width of the area into which the text is being painted changes, return to step 2. If the text to be painted changes, return to step 1.
Summary
Public constructors |
|
|---|---|
<init>(text: AnnotatedString, style: TextStyle, maxLines: Int = Int.MAX_VALUE, softWrap: Boolean = true, overflow: TextOverflow = TextOverflow.Clip, density: Density, layoutDirection: LayoutDirection, resourceLoader: Font.ResourceLoader)An object that paints text onto a Canvas. |
|
Public methods |
|
|---|---|
| TextLayoutResult |
layout(constraints: Constraints, prevResult: TextLayoutResult? = null) |
| Unit | |
| Unit |
paint(canvas: Canvas, textLayoutResult: TextLayoutResult)Paints the text onto the given canvas. |
| Unit |
paintBackground(start: Int, end: Int, color: Color, canvas: Canvas, textLayoutResult: TextLayoutResult)Draws text background of the given range. |
Properties |
|
|---|---|
| Density | |
| LayoutDirection |
The composable layout direction. |
| IntPx |
The width at which increasing the width of the text no longer decreases the height. |
| Int |
An optional maximum number of lines for the text to span, wrapping if necessary. |
| IntPx |
The width for text if all soft wrap opportunities were taken. |
| TextOverflow |
How visual overflow should be handled. |
| Font.ResourceLoader | |
| Boolean |
Whether the text should break at soft line breaks. |
| TextStyle | |
| AnnotatedString |
the text to paint. |
Public constructors
<init>
TextDelegate(
text: AnnotatedString,
style: TextStyle,
maxLines: Int = Int.MAX_VALUE,
softWrap: Boolean = true,
overflow: TextOverflow = TextOverflow.Clip,
density: Density,
layoutDirection: LayoutDirection,
resourceLoader: Font.ResourceLoader)
An object that paints text onto a Canvas.
To use a TextDelegate, follow these steps:
- Create an AnnotatedString and pass it to the TextDelegate constructor.
- Call layout to prepare the paragraph.
- Call paint as often as desired to paint the paragraph.
If the width of the area into which the text is being painted changes, return to step 2. If the text to be painted changes, return to step 1.
| Parameters | |
|---|---|
| text: AnnotatedString | the text to paint. |
| style: TextStyle | The text style specified to render the text. Notice that you can also set text style on the given AnnotatedString, and the style set on text always has higher priority than this setting. But if only one global text style is needed, passing it to TextDelegate is always preferred. |
| maxLines: Int = Int.MAX_VALUE | An optional maximum number of lines for the text to span, wrapping if necessary. If the text exceeds the given number of lines, it is truncated such that subsequent lines are dropped. |
| softWrap: Boolean = true | Whether the text should break at soft line breaks. If false, the glyphs in the text will be positioned as if there was unlimited horizontal space. If softWrap is false, overflow and TextAlign may have unexpected effects. |
| overflow: TextOverflow = TextOverflow.Clip | How visual overflow should be handled. Specifically, the ellipsis is applied to the last line before the line truncated by maxLines, if maxLines is non-null and that line overflows the width constraint. |
| layoutDirection: LayoutDirection | The composable layout direction. |
Public methods
layout
fun layout(
constraints: Constraints,
prevResult: TextLayoutResult? = null
): TextLayoutResult
layoutIntrinsics
fun layoutIntrinsics(): Unit
paint
fun paint(
canvas: Canvas,
textLayoutResult: TextLayoutResult
): Unit
Paints the text onto the given canvas.
Valid only after layout has been called.
If you cannot see the text being painted, check that your text color does not conflict with the background on which you are drawing. The default text color is white (to contrast with the default black background color), so if you are writing an application with a white background, the text will not be visible by default.
To set the text style, specify a SpanStyle when creating the AnnotatedString that you pass to the TextDelegate constructor or to the text property.
paintBackground
fun paintBackground(
start: Int,
end: Int,
color: Color,
canvas: Canvas,
textLayoutResult: TextLayoutResult
): Unit
Draws text background of the given range.
If the given range is empty, do nothing.
| Parameters | |
|---|---|
| start: Int | inclusive start character offset of the drawing range. |
| end: Int | exclusive end character offset of the drawing range. |
| color: Color | a color to be used for drawing background. |
| canvas: Canvas | the target canvas. |
Properties
density
val density: Density
maxIntrinsicWidth
val maxIntrinsicWidth: IntPx
The width at which increasing the width of the text no longer decreases the height.
Valid only after layout has been called.
maxLines
val maxLines: Int
An optional maximum number of lines for the text to span, wrapping if necessary. If the text exceeds the given number of lines, it is truncated such that subsequent lines are dropped.
minIntrinsicWidth
val minIntrinsicWidth: IntPx
The width for text if all soft wrap opportunities were taken.
Valid only after layout has been called.
overflow
val overflow: TextOverflow
How visual overflow should be handled. Specifically, the ellipsis is applied to the last line before the line truncated by maxLines, if maxLines is non-null and that line overflows the width constraint.
resourceLoader
val resourceLoader: Font.ResourceLoader
softWrap
val softWrap: Boolean
Whether the text should break at soft line breaks. If false, the glyphs in the text will be positioned as if there was unlimited horizontal space. If softWrap is false, overflow and TextAlign may have unexpected effects.
style
val style: TextStyle