jdk.awt.font.TextLayout — clojure-interop/java.awt 1.0.5

TextLayout is an immutable graphical representation of styled character data.

It provides the following capabilities:

implicit bidirectional analysis and reordering, cursor positioning and movement, including split cursors for mixed directional text, highlighting, including both logical and visual highlighting for mixed directional text, multiple baselines (roman, hanging, and centered), hit testing, justification, default font substitution, metric information such as ascent, descent, and advance, and rendering

A TextLayout object can be rendered using its draw method.

TextLayout can be constructed either directly or through the use of a LineBreakMeasurer. When constructed directly, the source text represents a single paragraph. LineBreakMeasurer allows styled text to be broken into lines that fit within a particular width. See the LineBreakMeasurer documentation for more information.

TextLayout construction logically proceeds as follows:

paragraph attributes are extracted and examined, text is analyzed for bidirectional reordering, and reordering information is computed if needed, text is segmented into style runs fonts are chosen for style runs, first by using a font if the attribute TextAttribute.FONT is present, otherwise by computing a default font using the attributes that have been defined if text is on multiple baselines, the runs or subruns are further broken into subruns sharing a common baseline, glyphvectors are generated for each run using the chosen font, final bidirectional reordering is performed on the glyphvectors

All graphical information returned from a TextLayout object's methods is relative to the origin of the TextLayout, which is the intersection of the TextLayout object's baseline with its left edge. Also, coordinates passed into a TextLayout object's methods are assumed to be relative to the TextLayout object's origin. Clients usually need to translate between a TextLayout object's coordinate system and the coordinate system in another object (such as a Graphics object).

TextLayout objects are constructed from styled text, but they do not retain a reference to their source text. Thus, changes in the text previously used to generate a TextLayout do not affect the TextLayout.

Three methods on a TextLayout object (getNextRightHit, getNextLeftHit, and hitTestChar) return instances of TextHitInfo. The offsets contained in these TextHitInfo objects are relative to the start of the TextLayout, not to the text used to create the TextLayout. Similarly, TextLayout methods that accept TextHitInfo instances as parameters expect the TextHitInfo object's offsets to be relative to the TextLayout, not to any underlying text storage model.

Examples: Constructing and drawing a TextLayout and its bounding rectangle:

Graphics2D g = ...; Point2D loc = ...; Font font = Font.getFont("Helvetica-bold-italic"); FontRenderContext frc = g.getFontRenderContext(); TextLayout layout = new TextLayout("This is a string", font, frc); layout.draw(g, (float)loc.getX(), (float)loc.getY());

Rectangle2D bounds = layout.getBounds(); bounds.setRect(bounds.getX()+loc.getX(), bounds.getY()+loc.getY(), bounds.getWidth(), bounds.getHeight()); g.draw(bounds);

Hit-testing a TextLayout (determining which character is at a particular graphical location):

Point2D click = ...; TextHitInfo hit = layout.hitTestChar( (float) (click.getX() - loc.getX()), (float) (click.getY() - loc.getY()));

Responding to a right-arrow key press:

int insertionIndex = ...; TextHitInfo next = layout.getNextRightHit(insertionIndex); if (next != null) { // translate graphics to origin of layout on screen g.translate(loc.getX(), loc.getY()); Shape[] carets = layout.getCaretShapes(next.getInsertionIndex()); g.draw(carets[0]); if (carets[1] != null) { g.draw(carets[1]); } }

Drawing a selection range corresponding to a substring in the source text. The selected area may not be visually contiguous:

// selStart, selLimit should be relative to the layout, // not to the source text

int selStart = ..., selLimit = ...; Color selectionColor = ...; Shape selection = layout.getLogicalHighlightShape(selStart, selLimit); // selection may consist of disjoint areas // graphics is assumed to be tranlated to origin of layout g.setColor(selectionColor); g.fill(selection);

Drawing a visually contiguous selection range. The selection range may correspond to more than one substring in the source text. The ranges of the corresponding source text substrings can be obtained with getLogicalRangesForVisualSelection():

TextHitInfo selStart = ..., selLimit = ...; Shape selection = layout.getVisualHighlightShape(selStart, selLimit); g.setColor(selectionColor); g.fill(selection); int[] ranges = getLogicalRangesForVisualSelection(selStart, selLimit); // ranges[0], ranges[1] is the first selection range, // ranges[2], ranges[3] is the second selection range, etc.

Note: Font rotations can cause text baselines to be rotated, and multiple runs with different rotations can cause the baseline to bend or zig-zag. In order to account for this (rare) possibility, some APIs are specified to return metrics and take parameters 'in baseline-relative coordinates' (e.g. ascent, advance), and others are in 'in standard coordinates' (e.g. getBounds). Values in baseline-relative coordinates map the 'x' coordinate to the distance along the baseline, (positive x is forward along the baseline), and the 'y' coordinate to a distance along the perpendicular to the baseline at 'x' (positive y is 90 degrees clockwise from the baseline vector). Values in standard coordinates are measured along the x and y axes, with 0,0 at the origin of the TextLayout. Documentation for each relevant API indicates what values are in what coordinate system. In general, measurement-related APIs are in baseline-relative coordinates, while display-related APIs are in standard coordinates.

*-default-caret-policy clj

Static Constant.

This CaretPolicy is used when a policy is not specified by the client. With this policy, a hit on a character whose direction is the same as the line direction is stronger than a hit on a counterdirectional character. If the characters' directions are the same, a hit on the leading edge of a character is stronger than a hit on the trailing edge of a character.

type: java.awt.font.TextLayout$CaretPolicy

->text-layout clj

(->text-layout text frc)

(->text-layout string font frc)

Constructor.

Constructs a TextLayout from a String and a Font. All the text is styled using the specified Font.

The String must specify a single paragraph of text, because an entire paragraph is required for the bidirectional algorithm.

string - the text to display - java.lang.String font - a Font used to style the text - java.awt.Font frc - contains information about a graphics device which is needed to measure the text correctly. Text measurements can vary slightly depending on the device resolution, and attributes such as antialiasing. This parameter does not specify a translation between the TextLayout and user space. - java.awt.font.FontRenderContext

draw clj

(draw this g-2 x y)

Renders this TextLayout at the specified location in the specified Graphics2D context. The origin of the layout is placed at x, y. Rendering may touch any point within getBounds() of this position. This leaves the g2 unchanged. Text is rendered along the baseline path.

g-2 - the Graphics2D context into which to render the layout - java.awt.Graphics2D x - the X coordinate of the origin of this TextLayout - float y - the Y coordinate of the origin of this TextLayout - float

equals clj

(equals this obj)

Returns true if the specified Object is a TextLayout object and if the specified Object equals this TextLayout.

obj - an Object to test for equality - java.lang.Object

returns: true if the specified Object equals this TextLayout; false otherwise. - boolean

get-advance clj

(get-advance this)

Returns the advance of this TextLayout. The advance is the distance from the origin to the advance of the rightmost (bottommost) character. This is in baseline-relative coordinates.

returns: the advance of this TextLayout. - float

get-ascent clj

(get-ascent this)

Returns the ascent of this TextLayout. The ascent is the distance from the top (right) of the TextLayout to the baseline. It is always either positive or zero. The ascent is sufficient to accommodate superscripted text and is the maximum of the sum of the ascent, offset, and baseline of each glyph. The ascent is the maximum ascent from the baseline of all the text in the TextLayout. It is in baseline-relative coordinates.

returns: the ascent of this TextLayout. - float

get-baseline clj

(get-baseline this)

Returns the baseline for this TextLayout. The baseline is one of the values defined in Font, which are roman, centered and hanging. Ascent and descent are relative to this baseline. The baselineOffsets are also relative to this baseline.

returns: the baseline of this TextLayout. - byte

get-baseline-offsets clj

(get-baseline-offsets this)

Returns the offsets array for the baselines used for this TextLayout.

The array is indexed by one of the values defined in Font, which are roman, centered and hanging. The values are relative to this TextLayout object's baseline, so that getBaselineOffsets[getBaseline()] == 0. Offsets are added to the position of the TextLayout object's baseline to get the position for the new baseline.

returns: the offsets array containing the baselines used for this TextLayout. - float[]

get-black-box-bounds clj

(get-black-box-bounds this first-endpoint second-endpoint)

Returns the black box bounds of the characters in the specified range. The black box bounds is an area consisting of the union of the bounding boxes of all the glyphs corresponding to the characters between start and limit. This area can be disjoint.

first-endpoint - one end of the character range - int second-endpoint - the other end of the character range. Can be less than firstEndpoint. - int

returns: a Shape enclosing the black box bounds. This is in standard coordinates. - java.awt.Shape

get-bounds clj

(get-bounds this)

Returns the bounds of this TextLayout. The bounds are in standard coordinates. Due to rasterization effects, this bounds might not enclose all of the pixels rendered by the TextLayout. It might not coincide exactly with the ascent, descent, origin or advance of the TextLayout.

returns: a Rectangle2D that is the bounds of this TextLayout. - java.awt.geom.Rectangle2D

get-caret-info clj

(get-caret-info this hit)

(get-caret-info this hit bounds)

Returns information about the caret corresponding to hit. The first element of the array is the intersection of the caret with the baseline, as a distance along the baseline. The second element of the array is the inverse slope (run/rise) of the caret, measured with respect to the baseline at that point.

This method is meant for informational use. To display carets, it is better to use getCaretShapes.

hit - a hit on a character in this TextLayout - java.awt.font.TextHitInfo bounds - the bounds to which the caret info is constructed. The bounds is in baseline-relative coordinates. - java.awt.geom.Rectangle2D

returns: a two-element array containing the position and slope of the caret. The returned caret info is in baseline-relative coordinates. - float[]

get-caret-shape clj

(get-caret-shape this hit)

(get-caret-shape this hit bounds)

Returns a Shape representing the caret at the specified hit inside the specified bounds.

hit - the hit at which to generate the caret - java.awt.font.TextHitInfo bounds - the bounds of the TextLayout to use in generating the caret. The bounds is in baseline-relative coordinates. - java.awt.geom.Rectangle2D

returns: a Shape representing the caret. The returned shape is in standard coordinates. - java.awt.Shape

get-caret-shapes clj

(get-caret-shapes this offset)

(get-caret-shapes this offset bounds)

(get-caret-shapes this offset bounds policy)

Returns two paths corresponding to the strong and weak caret.

offset - an offset in this TextLayout - int bounds - the bounds to which to extend the carets. The bounds is in baseline-relative coordinates. - java.awt.geom.Rectangle2D policy - the specified CaretPolicy - java.awt.font.TextLayout$CaretPolicy

returns: an array of two paths. Element zero is the strong caret. If there are two carets, element one is the weak caret, otherwise it is null. The returned shapes are in standard coordinates. - java.awt.Shape[]

get-character-count clj

(get-character-count this)

Returns the number of characters represented by this TextLayout.

returns: the number of characters in this TextLayout. - int

get-character-level clj

(get-character-level this index)

Returns the level of the character at index. Indices -1 and characterCount are assigned the base level of this TextLayout.

index - the index of the character from which to get the level - int

returns: the level of the character at the specified index. - byte

get-descent clj

(get-descent this)

Returns the descent of this TextLayout. The descent is the distance from the baseline to the bottom (left) of the TextLayout. It is always either positive or zero. The descent is sufficient to accommodate subscripted text and is the maximum of the sum of the descent, offset, and baseline of each glyph. This is the maximum descent from the baseline of all the text in the TextLayout. It is in baseline-relative coordinates.

returns: the descent of this TextLayout. - float

get-justified-layout clj

(get-justified-layout this justification-width)

Creates a copy of this TextLayout justified to the specified width.

If this TextLayout has already been justified, an exception is thrown. If this TextLayout object's justification ratio is zero, a TextLayout identical to this TextLayout is returned.

justification-width - the width to use when justifying the line. For best results, it should not be too different from the current advance of the line. - float

returns: a TextLayout justified to the specified width. - java.awt.font.TextLayout

throws: java.lang.Error - if this layout has already been justified, an Error is thrown.

get-layout-path clj

(get-layout-path this)

Return the LayoutPath, or null if the layout path is the default path (x maps to advance, y maps to offset).

returns: the layout path - java.awt.font.LayoutPath

get-leading clj

(get-leading this)

Returns the leading of the TextLayout. The leading is the suggested interline spacing for this TextLayout. This is in baseline-relative coordinates.

The leading is computed from the leading, descent, and baseline of all glyphvectors in the TextLayout. The algorithm is roughly as follows:

maxD = 0; maxDL = 0; for (GlyphVector g in all glyphvectors) { maxD = max(maxD, g.getDescent() offsets[g.getBaseline()]); maxDL = max(maxDL, g.getDescent() g.getLeading() offsets[g.getBaseline()]); } return maxDL - maxD;

returns: the leading of this TextLayout. - float

get-logical-highlight-shape clj

(get-logical-highlight-shape this first-endpoint second-endpoint)

(get-logical-highlight-shape this first-endpoint second-endpoint bounds)

Returns a Shape enclosing the logical selection in the specified range, extended to the specified bounds.

If the selection range includes the first logical character, the selection is extended to the portion of bounds before the start of this TextLayout. If the range includes the last logical character, the selection is extended to the portion of bounds after the end of this TextLayout. The height (width on vertical lines) of the selection is always extended to bounds.

The selection can be discontiguous on lines with mixed-direction text. Only those characters in the logical range between start and limit appear selected. For example, consider the text 'ABCdef' where capital letters indicate right-to-left text, rendered on a right-to-left line, with a logical selection from 0 to 4 ('ABCd'). The text appears as follows, with bold standing in for the selection, and underlining for the extension:

defCBA

The selection is discontiguous because the selected characters are visually discontiguous. Also note that since the range includes the first logical character (A), the selection is extended to the portion of the bounds before the start of the layout, which in this case (a right-to-left line) is the right portion of the bounds.

first-endpoint - an endpoint in the range of characters to select - int second-endpoint - the other endpoint of the range of characters to select. Can be less than firstEndpoint. The range includes the character at min(firstEndpoint, secondEndpoint), but excludes max(firstEndpoint, secondEndpoint). - int bounds - the bounding rectangle to which to extend the selection. This is in baseline-relative coordinates. - java.awt.geom.Rectangle2D

returns: an area enclosing the selection. This is in standard coordinates. - java.awt.Shape

get-logical-ranges-for-visual-selection clj

(get-logical-ranges-for-visual-selection this first-endpoint second-endpoint)

Returns the logical ranges of text corresponding to a visual selection.

first-endpoint - an endpoint of the visual range - java.awt.font.TextHitInfo second-endpoint - the other endpoint of the visual range. This endpoint can be less than firstEndpoint. - java.awt.font.TextHitInfo

returns: an array of integers representing start/limit pairs for the selected ranges. - int[]

get-next-left-hit clj

(get-next-left-hit this hit)

(get-next-left-hit this offset policy)

Returns the hit for the next caret to the left (top); if no such hit, returns null. The hit is to the left of the strong caret at the specified offset, as determined by the specified policy. The returned hit is the stronger of the two possible hits, as determined by the specified policy.

offset - an insertion offset in this TextLayout. Cannot be less than 0 or greater than this TextLayout object's character count. - int policy - the policy used to select the strong caret - java.awt.font.TextLayout$CaretPolicy

returns: a hit whose caret appears at the next position to the left (top) of the caret of the provided hit, or null. - java.awt.font.TextHitInfo

get-next-right-hit clj

(get-next-right-hit this hit)

(get-next-right-hit this offset policy)

Returns the hit for the next caret to the right (bottom); if no such hit, returns null. The hit is to the right of the strong caret at the specified offset, as determined by the specified policy. The returned hit is the stronger of the two possible hits, as determined by the specified policy.

offset - an insertion offset in this TextLayout. Cannot be less than 0 or greater than this TextLayout object's character count. - int policy - the policy used to select the strong caret - java.awt.font.TextLayout$CaretPolicy

returns: a hit whose caret appears at the next position to the right (bottom) of the caret of the provided hit, or null. - java.awt.font.TextHitInfo

get-outline clj

(get-outline this tx)

Returns a Shape representing the outline of this TextLayout.

tx - an optional AffineTransform to apply to the outline of this TextLayout. - java.awt.geom.AffineTransform

returns: a Shape that is the outline of this TextLayout. This is in standard coordinates. - java.awt.Shape

get-pixel-bounds clj

(get-pixel-bounds this frc x y)

Returns the pixel bounds of this TextLayout when rendered in a graphics with the given FontRenderContext at the given location. The graphics render context need not be the same as the FontRenderContext used to create this TextLayout, and can be null. If it is null, the FontRenderContext of this TextLayout is used.

frc - the FontRenderContext of the Graphics. - java.awt.font.FontRenderContext x - the x-coordinate at which to render this TextLayout. - float y - the y-coordinate at which to render this TextLayout. - float

returns: a Rectangle bounding the pixels that would be affected. - java.awt.Rectangle

get-visible-advance clj

(get-visible-advance this)

Returns the advance of this TextLayout, minus trailing whitespace. This is in baseline-relative coordinates.

returns: the advance of this TextLayout without the trailing whitespace. - float

get-visual-highlight-shape clj

(get-visual-highlight-shape this first-endpoint second-endpoint)

(get-visual-highlight-shape this first-endpoint second-endpoint bounds)

Returns a path enclosing the visual selection in the specified range, extended to bounds.

If the selection includes the leftmost (topmost) position, the selection is extended to the left (top) of bounds. If the selection includes the rightmost (bottommost) position, the selection is extended to the right (bottom) of the bounds. The height (width on vertical lines) of the selection is always extended to bounds.

Although the selection is always contiguous, the logically selected text can be discontiguous on lines with mixed-direction text. The logical ranges of text selected can be retrieved using getLogicalRangesForVisualSelection. For example, consider the text 'ABCdef' where capital letters indicate right-to-left text, rendered on a right-to-left line, with a visual selection from 0L (the leading edge of 'A') to 3T (the trailing edge of 'd'). The text appears as follows, with bold underlined areas representing the selection:

defCBA

The logical selection ranges are 0-3, 4-6 (ABC, ef) because the visually contiguous text is logically discontiguous. Also note that since the rightmost position on the layout (to the right of 'A') is selected, the selection is extended to the right of the bounds.

first-endpoint - one end of the visual selection - java.awt.font.TextHitInfo second-endpoint - the other end of the visual selection - java.awt.font.TextHitInfo bounds - the bounding rectangle to which to extend the selection. This is in baseline-relative coordinates. - java.awt.geom.Rectangle2D

returns: a Shape enclosing the selection. This is in standard coordinates. - java.awt.Shape

get-visual-other-hit clj

(get-visual-other-hit this hit)

Returns the hit on the opposite side of the specified hit's caret.

hit - the specified hit - java.awt.font.TextHitInfo

returns: a hit that is on the opposite side of the specified hit's caret. - java.awt.font.TextHitInfo

hash-code clj

(hash-code this)

Returns the hash code of this TextLayout.

returns: the hash code of this TextLayout. - int

hit-test-char clj

(hit-test-char this x y)

(hit-test-char this x y bounds)

Returns a TextHitInfo corresponding to the specified point. Coordinates outside the bounds of the TextLayout map to hits on the leading edge of the first logical character, or the trailing edge of the last logical character, as appropriate, regardless of the position of that character in the line. Only the direction along the baseline is used to make this evaluation.

x - the x offset from the origin of this TextLayout. This is in standard coordinates. - float y - the y offset from the origin of this TextLayout. This is in standard coordinates. - float bounds - the bounds of the TextLayout. This is in baseline-relative coordinates. - java.awt.geom.Rectangle2D

returns: a hit describing the character and edge (leading or trailing) under the specified point. - java.awt.font.TextHitInfo

hit-to-point clj

(hit-to-point this hit point)

Convert a hit to a point in standard coordinates. The point is on the baseline of the character at the leading or trailing edge of the character, as appropriate. If the path is broken at the side of the character represented by the hit, the point will be adjacent to the character.

hit - the hit to check. This must be a valid hit on the TextLayout. - java.awt.font.TextHitInfo point - the returned point. The point is in standard coordinates. - java.awt.geom.Point2D

throws: java.lang.IllegalArgumentException - if the hit is not valid for the TextLayout.

left-to-right? clj

(left-to-right? this)

Returns true if this TextLayout has a left-to-right base direction or false if it has a right-to-left base direction. The TextLayout has a base direction of either left-to-right (LTR) or right-to-left (RTL). The base direction is independent of the actual direction of text on the line, which may be either LTR, RTL, or mixed. Left-to-right layouts by default should position flush left. If the layout is on a tabbed line, the tabs run left to right, so that logically successive layouts position left to right. The opposite is true for RTL layouts. By default they should position flush left, and tabs run right-to-left.

returns: true if the base direction of this TextLayout is left-to-right; false otherwise. - boolean

to-string clj

(to-string this)

Returns debugging information for this TextLayout.

returns: the textLine of this TextLayout as a String. - java.lang.String

vertical? clj

(vertical? this)

Returns true if this TextLayout is vertical.

returns: true if this TextLayout is vertical; false otherwise. - boolean