Paragraph


A paragraph of text that is laid out.

Paragraphs can be displayed on a Canvas using the paint method.

Summary

Public functions

Unit
fillBoundingBoxes(
    range: TextRange,
    array: FloatArray,
    arrayStart: @IntRange(from = 0) Int
)

Fills the bounding boxes for characters provided in the range into array.

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ResolvedTextDirection

Get the text direction of the character at the given offset.

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Rect

Returns the bounding box as Rect of the character for given character offset.

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Rect
getCursorRect(offset: Int)

Returns rectangle of the cursor area.

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Float
getHorizontalPosition(offset: Int, usePrimaryDirection: Boolean)

Compute the horizontal position where a newly inserted character at offset would be.

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Float
getLineBaseline(lineIndex: Int)

Returns the distance from the top of the paragraph to the alphabetic baseline of the given line.

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Float
getLineBottom(lineIndex: Int)

Returns the bottom y coordinate of the given line.

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Int
getLineEnd(lineIndex: Int, visibleEnd: Boolean)

Returns the end offset of the given line

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Int

Returns the line number on which the specified text offset appears.

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Int

Returns line number closest to the given graphical vertical position.

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Float
getLineHeight(lineIndex: Int)

Returns the height of the given line.

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Float
getLineLeft(lineIndex: Int)

Returns the left x Coordinate of the given line.

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Float
getLineRight(lineIndex: Int)

Returns the right x Coordinate of the given line.

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Int
getLineStart(lineIndex: Int)

Returns the start offset of the given line, inclusive.

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Float
getLineTop(lineIndex: Int)

Returns the bottom y coordinate of the given line.

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Float
getLineWidth(lineIndex: Int)

Returns the width of the given line.

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Int

Returns the character offset closest to the given graphical position.

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ResolvedTextDirection

Get the text direction of the paragraph containing the given offset.

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Path
getPathForRange(start: Int, end: Int)

Returns path that enclose the given text range.

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TextRange

Returns the TextRange of the word at the given character offset.

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Boolean
isLineEllipsized(lineIndex: Int)

Returns true if the given line is ellipsized, otherwise returns false.

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Unit
paint(
    canvas: Canvas,
    color: Color,
    shadow: Shadow?,
    textDecoration: TextDecoration?,
    drawStyle: DrawStyle?,
    blendMode: BlendMode
)

Draws this paragraph onto given canvas while modifying supported draw properties.

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Unit
paint(
    canvas: Canvas,
    brush: Brush,
    alpha: Float,
    shadow: Shadow?,
    textDecoration: TextDecoration?,
    drawStyle: DrawStyle?,
    blendMode: BlendMode
)

Draws this paragraph onto given canvas while modifying supported draw properties.

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Public properties

Boolean

True if there is more vertical content, but the text was truncated, either because we reached maxLines lines of text or because the maxLines was null, ellipsis was not null, and one of the lines exceeded the width constraint.

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Float

The distance from the top of the paragraph to the alphabetic baseline of the first line, in logical pixels.

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Float

The amount of vertical space this paragraph occupies.

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Float

The distance from the top of the paragraph to the alphabetic baseline of the last line, in logical pixels.

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Int

The total number of lines in the text.

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Float

Returns the smallest width beyond which increasing the width never decreases the height.

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Float

The width for text if all soft wrap opportunities were taken.

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List<Rect?>

The bounding boxes reserved for the input placeholders in this Paragraphs.

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Float

The amount of horizontal space this paragraph occupies.

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Public functions

fillBoundingBoxes

fun fillBoundingBoxes(
    range: TextRange,
    array: FloatArray,
    arrayStart: @IntRange(from = 0) Int
): Unit

Fills the bounding boxes for characters provided in the range into array. The array is filled starting from arrayStart (inclusive). The coordinates are in local text layout coordinates.

The returned information consists of left/right of a character; line top and bottom for the same character.

For the grapheme consists of multiple code points, e.g. ligatures, combining marks, the first character has the total width and the remaining are returned as zero-width.

The array divided into segments of four where each index in that segment represents left, top, right, bottom of the character.

The size of the provided array should be greater or equal than the four times * TextRange length.

The final order of characters in the array is from TextRange.min to TextRange.max.

Parameters
range: TextRange

the TextRange representing the start and end indices in the Paragraph.

array: FloatArray

the array to fill in the values. The array divided into segments of four where each index in that segment represents left, top, right, bottom of the character.

arrayStart: @IntRange(from = 0) Int

the inclusive start index in the array where the function will start filling in the values from

getBidiRunDirection

fun getBidiRunDirection(offset: Int): ResolvedTextDirection

Get the text direction of the character at the given offset.

getBoundingBox

fun getBoundingBox(offset: Int): Rect

Returns the bounding box as Rect of the character for given character offset. Rect includes the top, bottom, left and right of a character.

getCursorRect

fun getCursorRect(offset: Int): Rect

Returns rectangle of the cursor area.

getHorizontalPosition

fun getHorizontalPosition(offset: Int, usePrimaryDirection: Boolean): Float

Compute the horizontal position where a newly inserted character at offset would be.

If the inserted character at offset is within a LTR/RTL run, the returned position will be the left(right) edge of the character.

For example:
Paragraph's direction is LTR.
Text in logic order: L0 L1 L2 R3 R4 R5
Text in visual order: L0 L1 L2 R5 R4 R3
position of the offset(2): |
position of the offset(4): |

However, when the offset is at the BiDi transition offset, there will be two possible visual positions, which depends on the direction of the inserted character.

For example:
Paragraph's direction is LTR.
Text in logic order: L0 L1 L2 R3 R4 R5
Text in visual order: L0 L1 L2 R5 R4 R3
position of the offset(3): | (The inserted character is LTR)
| (The inserted character is RTL)

In this case, usePrimaryDirection will be used to resolve the ambiguity. If true, the inserted character's direction is assumed to be the same as Paragraph's direction. Otherwise, the inserted character's direction is assumed to be the opposite of the Paragraph's direction.

For example:
Paragraph's direction is LTR.
Text in logic order: L0 L1 L2 R3 R4 R5
Text in visual order: L0 L1 L2 R5 R4 R3
position of the offset(3): | (usePrimaryDirection is true)
| (usePrimaryDirection is false)

This method is useful to compute cursor position.

Parameters
offset: Int

the offset of the character, in the range of 0, length.

usePrimaryDirection: Boolean

whether the paragraph direction is respected when offset points to a BiDi transition point.

Returns
Float

a float number representing the horizontal position in the unit of pixel.

getLineBaseline

fun getLineBaseline(lineIndex: Int): Float

Returns the distance from the top of the paragraph to the alphabetic baseline of the given line.

getLineBottom

fun getLineBottom(lineIndex: Int): Float

Returns the bottom y coordinate of the given line.

getLineEnd

fun getLineEnd(lineIndex: Int, visibleEnd: Boolean = false): Int

Returns the end offset of the given line

Characters being ellipsized are treated as invisible characters. So that if visibleEnd is false, it will return line end including the ellipsized characters and vice verse.

Parameters
lineIndex: Int

the line number

visibleEnd: Boolean = false

if true, the returned line end will not count trailing whitespaces or linefeed characters. Otherwise, this function will return the logical line end. By default it's false.

Returns
Int

an exclusive end offset of the line.

getLineForOffset

fun getLineForOffset(offset: Int): Int

Returns the line number on which the specified text offset appears. If you ask for a position before 0, you get 0; if you ask for a position beyond the end of the text, you get the last line.

getLineForVerticalPosition

fun getLineForVerticalPosition(vertical: Float): Int

Returns line number closest to the given graphical vertical position. If you ask for a vertical position before 0, you get 0; if you ask for a vertical position beyond the last line, you get the last line.

getLineHeight

fun getLineHeight(lineIndex: Int): Float

Returns the height of the given line.

getLineLeft

fun getLineLeft(lineIndex: Int): Float

Returns the left x Coordinate of the given line.

getLineRight

fun getLineRight(lineIndex: Int): Float

Returns the right x Coordinate of the given line.

getLineStart

fun getLineStart(lineIndex: Int): Int

Returns the start offset of the given line, inclusive.

getLineTop

fun getLineTop(lineIndex: Int): Float

Returns the bottom y coordinate of the given line.

getLineWidth

fun getLineWidth(lineIndex: Int): Float

Returns the width of the given line.

getOffsetForPosition

fun getOffsetForPosition(position: Offset): Int

Returns the character offset closest to the given graphical position.

getParagraphDirection

fun getParagraphDirection(offset: Int): ResolvedTextDirection

Get the text direction of the paragraph containing the given offset.

getPathForRange

fun getPathForRange(start: Int, end: Int): Path

Returns path that enclose the given text range.

getWordBoundary

fun getWordBoundary(offset: Int): TextRange

Returns the TextRange of the word at the given character offset. Characters not part of a word, such as spaces, symbols, and punctuation, have word breaks on both sides. In such cases, this method will return TextRange(offset, offset). Word boundaries are defined more precisely in Unicode Standard Annex #29 http://www.unicode.org/reports/tr29/#Word_Boundaries

isLineEllipsized

fun isLineEllipsized(lineIndex: Int): Boolean

Returns true if the given line is ellipsized, otherwise returns false.

Parameters
lineIndex: Int

a 0 based line index

Returns
Boolean

true if the given line is ellipsized, otherwise false

paint

fun paint(
    canvas: Canvas,
    color: Color = Color.Unspecified,
    shadow: Shadow? = null,
    textDecoration: TextDecoration? = null,
    drawStyle: DrawStyle? = null,
    blendMode: BlendMode = DrawScope.DefaultBlendMode
): Unit

Draws this paragraph onto given canvas while modifying supported draw properties. Any change caused by overriding parameters are permanent, meaning that they affect the subsequent paint calls.

Parameters
canvas: Canvas

Canvas to draw this paragraph on.

color: Color = Color.Unspecified

Applies to the default text paint color that's used by this paragraph. Text color spans are not affected. Color.Unspecified is treated as no-op.

shadow: Shadow? = null

Applies to the default text paint shadow that's used by this paragraph. Text shadow spans are not affected. Shadow.None removes any existing shadow on this paragraph, null does not change the currently set Shadow configuration.

textDecoration: TextDecoration? = null

Applies to the default text paint that's used by this paragraph. Spans that specify a TextDecoration are not affected. TextDecoration.None removes any existing TextDecoration on this paragraph, null does not change the currently set TextDecoration configuration.

drawStyle: DrawStyle? = null

Applies to the default text paint style that's used by this paragraph. Spans that specify a DrawStyle are not affected. Passing this value as null does not change the currently set DrawStyle.

blendMode: BlendMode = DrawScope.DefaultBlendMode

Blending algorithm to be applied to the Paragraph while painting.

paint

fun paint(
    canvas: Canvas,
    brush: Brush,
    alpha: Float = Float.NaN,
    shadow: Shadow? = null,
    textDecoration: TextDecoration? = null,
    drawStyle: DrawStyle? = null,
    blendMode: BlendMode = DrawScope.DefaultBlendMode
): Unit

Draws this paragraph onto given canvas while modifying supported draw properties. Any change caused by overriding parameters are permanent, meaning that they affect the subsequent paint calls.

Parameters
canvas: Canvas

Canvas to draw this paragraph on.

brush: Brush

Applies to the default text paint shader that's used by this paragraph. Text brush spans are not affected. If brush is type of SolidColor, color's alpha value is modulated by alpha parameter and gets applied as a color. If brush is type of ShaderBrush, its internal shader is created using this paragraph's layout size.

alpha: Float = Float.NaN

Applies to the default text paint alpha that's used by this paragraph. Text alpha spans are not affected. Float.NaN is treated as no-op. All other values are coerced into 0f, 1f range.

shadow: Shadow? = null

Applies to the default text paint shadow that's used by this paragraph. Text shadow spans are not affected. Shadow.None removes any existing shadow on this paragraph, null does not change the currently set Shadow configuration.

textDecoration: TextDecoration? = null

Applies to the default text paint that's used by this paragraph. Spans that specify a TextDecoration are not affected. TextDecoration.None removes any existing TextDecoration on this paragraph, null does not change the currently set TextDecoration configuration.

drawStyle: DrawStyle? = null

Applies to the default text paint style that's used by this paragraph. Spans that specify a DrawStyle are not affected. Passing this value as null does not change the currently set DrawStyle.

blendMode: BlendMode = DrawScope.DefaultBlendMode

Blending algorithm to be applied to the Paragraph while painting.

Public properties

didExceedMaxLines

val didExceedMaxLinesBoolean

True if there is more vertical content, but the text was truncated, either because we reached maxLines lines of text or because the maxLines was null, ellipsis was not null, and one of the lines exceeded the width constraint.

See the discussion of the maxLines and ellipsis arguments at ParagraphStyle.

firstBaseline

val firstBaselineFloat

The distance from the top of the paragraph to the alphabetic baseline of the first line, in logical pixels.

height

val heightFloat

The amount of vertical space this paragraph occupies.

lastBaseline

val lastBaselineFloat

The distance from the top of the paragraph to the alphabetic baseline of the last line, in logical pixels.

lineCount

val lineCountInt

The total number of lines in the text.

maxIntrinsicWidth

val maxIntrinsicWidthFloat

Returns the smallest width beyond which increasing the width never decreases the height.

minIntrinsicWidth

val minIntrinsicWidthFloat

The width for text if all soft wrap opportunities were taken.

placeholderRects

val placeholderRectsList<Rect?>

The bounding boxes reserved for the input placeholders in this Paragraphs. Their locations are relative to this Paragraph's coordinate. The order of this list corresponds to that of input placeholders. Notice that Rect in placeholderRects is nullable. When Rect is null, it indicates that the corresponding Placeholder is ellipsized.

width

val widthFloat

The amount of horizontal space this paragraph occupies.