playout.h File Reference

C API for paragraph layout. More...

`#include "unicode/ubidi.h"`
`#include "layout/LETypes.h"`
`#include "plruns.h"`

Go to the source code of this file.

## Typedefs

typedef void | pl_paragraph
| The opaque type for a paragraph layout. More...
typedef void | pl_line
| The opaque type for a line in a paragraph layout. More...
typedef void | pl_visualRun
| The opaque type for a visual run in a line. More...

## Functions

U_CAPI pl_paragraph * | pl_create (const LEUnicode chars[], le_int32 count, const pl_fontRuns *fontRuns, const pl_valueRuns *levelRuns, const pl_valueRuns *scriptRuns, const pl_localeRuns *localeRuns, UBiDiLevel paragraphLevel, le_bool vertical, LEErrorCode *status)
| Construct a `ParagraphLayout` object for a styled paragraph. More...
U_CAPI void | pl_close (pl_paragraph *paragraph)
| Close the given paragraph layout object. More...
U_CAPI le_bool | pl_isComplex (const LEUnicode chars[], le_int32 count)
| Examine the given text and determine if it contains characters in any script which requires complex processing to be rendered correctly. More...
U_CAPI UBiDiLevel | pl_getParagraphLevel (pl_paragraph *paragraph)
| Return the resolved paragraph level. More...
U_CAPI UBiDiDirection | pl_getTextDirection (pl_paragraph *paragraph)
| Return the directionality of the text in the paragraph. More...
U_CAPI le_int32 | pl_getAscent (const pl_paragraph *paragraph)
| Return the max ascent value for all the fonts in the paragraph. More...
U_CAPI le_int32 | pl_getDescent (const pl_paragraph *paragraph)
| Return the max descent value for all the fonts in the paragraph. More...
U_CAPI le_int32 | pl_getLeading (const pl_paragraph *paragraph)
| Return the max leading value for all the fonts in the paragraph. More...
U_CAPI void | pl_reflow (pl_paragraph *paragraph)
| Reset line breaking to start from the beginning of the paragraph. More...
U_CAPI pl_line * | pl_nextLine (pl_paragraph *paragraph, float width)
| Return a `pl_line` object which represents next line in the paragraph. More...
U_CAPI void | pl_closeLine (pl_line *line)
| Close the given line object. More...
U_CAPI le_int32 | pl_countLineRuns (const pl_line *line)
| Count the number of visual runs in the line. More...
U_CAPI le_int32 | pl_getLineAscent (const pl_line *line)
| Get the ascent of the line. More...
U_CAPI le_int32 | pl_getLineDescent (const pl_line *line)
| Get the descent of the line. More...
U_CAPI le_int32 | pl_getLineLeading (const pl_line *line)
| Get the leading of the line. More...
U_CAPI le_int32 | pl_getLineWidth (const pl_line *line)
| Get the width of the line. More...
U_CAPI const pl_visualRun * | pl_getLineVisualRun (const pl_line *line, le_int32 runIndex)
| Get a `ParagraphLayout::VisualRun` object for a given visual run in the line. More...
U_CAPI const le_font * | pl_getVisualRunFont (const pl_visualRun *run)
| Get the `le_font` object which represents the font of the visual run. More...
U_CAPI UBiDiDirection | pl_getVisualRunDirection (const pl_visualRun *run)
| Get the direction of the visual run. More...
U_CAPI le_int32 | pl_getVisualRunGlyphCount (const pl_visualRun *run)
| Get the number of glyphs in the visual run. More...
U_CAPI const LEGlyphID * | pl_getVisualRunGlyphs (const pl_visualRun *run)
| Get the glyphs in the visual run. More...
U_CAPI const float * | pl_getVisualRunPositions (const pl_visualRun *run)
| Get the (x, y) positions of the glyphs in the visual run. More...
U_CAPI const le_int32 * | pl_getVisualRunGlyphToCharMap (const pl_visualRun *run)
| Get the glyph-to-character map for this visual run. More...
U_CAPI le_int32 | pl_getVisualRunAscent (const pl_visualRun *run)
| A convenience method which returns the ascent value for the font associated with this run. More...
U_CAPI le_int32 | pl_getVisualRunDescent (const pl_visualRun *run)
| A convenience method which returns the descent value for the font associated with this run. More...
U_CAPI le_int32 | pl_getVisualRunLeading (const pl_visualRun *run)
| A convenience method which returns the leading value for the font associated with this run. More...

## Detailed Description

C API for paragraph layout.

This is a technology preview. The API may change significantly.

Definition in file playout.h.

## Typedef Documentation

## pl_line

typedef void pl_line

The opaque type for a line in a paragraph layout.

Internal:
  Do not use. This API is for internal use only.

Definition at line 44 of file playout.h.

## pl_paragraph

typedef void pl_paragraph

The opaque type for a paragraph layout.

Internal:
  Do not use. This API is for internal use only.

Definition at line 37 of file playout.h.

## pl_visualRun

typedef void pl_visualRun

The opaque type for a visual run in a line.

Internal:
  Do not use. This API is for internal use only.

Definition at line 51 of file playout.h.

## Function Documentation

## pl_close()

U_CAPI void pl_close | ( | pl_paragraph * | paragraph | ) |

Close the given paragraph layout object.

Parameters

  paragraph | the `pl_paragraph` object to be closed. Once this routine returns the object can no longer be referenced

Internal:
  Do not use. This API is for internal use only.

## pl_closeLine()

U_CAPI void pl_closeLine | ( | pl_line * | line | ) |

Close the given line object.

Line objects are created by `pl_nextLine` but it is the client's responsibility to close them by calling this routine.

Parameters

  line | the `pl_line` object to close.

Internal:
  Do not use. This API is for internal use only.

## pl_countLineRuns()

U_CAPI le_int32 pl_countLineRuns | ( | const pl_line * | line | ) |

Count the number of visual runs in the line.

Parameters

  line | the `pl_line` object.

Returns
  the number of visual runs.

Internal:
  Do not use. This API is for internal use only.

## pl_create()

U_CAPI pl_paragraph* pl_create | ( | const LEUnicode | chars[],
|  | le_int32 | count,
|  | const pl_fontRuns * | fontRuns,
|  | const pl_valueRuns * | levelRuns,
|  | const pl_valueRuns * | scriptRuns,
|  | const pl_localeRuns * | localeRuns,
|  | UBiDiLevel | paragraphLevel,
|  | le_bool | vertical,
|  | LEErrorCode * | status
| ) |  |

Construct a `ParagraphLayout` object for a styled paragraph.

The paragraph is specified as runs of text all in the same font. An `LEFontInstance` object and a limit offset are specified for each font run. The limit offset is the offset of the character immediately after the font run.

Clients can optionally specify directional runs and / or script runs. If these aren't specified they will be computed.

If any errors are encountered during construction, `status` will be set, and the object will be set to be empty.

Parameters

  chars | is an array of the characters in the paragraph
  count | is the number of characters in the paragraph.
  fontRuns | a pointer to a `pl_fontRuns` object representing the font runs.
  levelRuns | is a pointer to a `pl_valueRuns` object representing the directional levels. If this pointer in `NULL` the levels will be determined by running the Unicode Bidi algorithm.
  scriptRuns | is a pointer to a `pl_valueRuns` object representing script runs. If this pointer in `NULL` the script runs will be determined using the Unicode code points.
  localeRuns | is a pointer to a `pl_localeRuns` object representing locale runs. The `Locale` objects are used to determine the language of the text. If this pointer is `NULL` the default locale will be used for all of the text.
  paragraphLevel | is the directionality of the paragraph, as in the UBiDi object.
  vertical | is `true` if the paragraph should be set vertically.
  status | will be set to any error code encountered during construction.

Returns
  a pointer to the newly created `pl_paragraph` object. The object will remain valid until `pl_close` is called.

See also
  ubidi.h
  longine.h
  plruns.h

Internal:
  Do not use. This API is for internal use only.

## pl_getAscent()

U_CAPI le_int32 pl_getAscent | ( | const pl_paragraph * | paragraph | ) |

Return the max ascent value for all the fonts in the paragraph.

Parameters

  paragraph | the `pl_paragraph`

Returns
  the ascent value.

Internal:
  Do not use. This API is for internal use only.

## pl_getDescent()

U_CAPI le_int32 pl_getDescent | ( | const pl_paragraph * | paragraph | ) |

Return the max descent value for all the fonts in the paragraph.

Parameters

  paragraph | the `pl_paragraph`

Returns
  the decent value.

Internal:
  Do not use. This API is for internal use only.

## pl_getLeading()

U_CAPI le_int32 pl_getLeading | ( | const pl_paragraph * | paragraph | ) |

Return the max leading value for all the fonts in the paragraph.

Parameters

  paragraph | the `pl_paragraph`

Returns
  the leading value.

Internal:
  Do not use. This API is for internal use only.

## pl_getLineAscent()

U_CAPI le_int32 pl_getLineAscent | ( | const pl_line * | line | ) |

Get the ascent of the line.

This is the maximum ascent of all the fonts on the line.

Parameters

  line | the `pl_line` object.

Returns
  the ascent of the line.

Internal:
  Do not use. This API is for internal use only.

## pl_getLineDescent()

U_CAPI le_int32 pl_getLineDescent | ( | const pl_line * | line | ) |

Get the descent of the line.

This is the maximum descent of all the fonts on the line.

Parameters

  line | the `pl_line` object.

Returns
  the descent of the line.

Internal:
  Do not use. This API is for internal use only.

## pl_getLineLeading()

U_CAPI le_int32 pl_getLineLeading | ( | const pl_line * | line | ) |

Get the leading of the line.

This is the maximum leading of all the fonts on the line.

Parameters

  line | the `pl_line` object.

Returns
  the leading of the line.

Internal:
  Do not use. This API is for internal use only.

## pl_getLineVisualRun()

U_CAPI const pl_visualRun* pl_getLineVisualRun | ( | const pl_line * | line,
|  | le_int32 | runIndex
| ) |  |

Get a `ParagraphLayout::VisualRun` object for a given visual run in the line.

Parameters

  line | the `pl_line` object.
  runIndex | is the index of the run, in visual order.

Returns
  the `pl_visualRun` object representing the visual run. This object is owned by the `pl_line` object which created it, and will remain valid for as long as the `pl_line` object is valid.

See also
  pl_visualRun

Internal:
  Do not use. This API is for internal use only.

## pl_getLineWidth()

U_CAPI le_int32 pl_getLineWidth | ( | const pl_line * | line | ) |

Get the width of the line.

This is a convenience method which returns the last X position of the last visual run in the line.

Parameters

  line | the `pl_line` object.

Returns
  the width of the line.

Internal:
  Do not use. This API is for internal use only.

## pl_getParagraphLevel()

U_CAPI UBiDiLevel pl_getParagraphLevel | ( | pl_paragraph * | paragraph | ) |

Return the resolved paragraph level.

This is useful for those cases where the bidi analysis has determined the level based on the first strong character in the paragraph.

Parameters

  paragraph | the `pl_paragraph`

Returns
  the resolved paragraph level.

Internal:
  Do not use. This API is for internal use only.

## pl_getTextDirection()

U_CAPI UBiDiDirection pl_getTextDirection | ( | pl_paragraph * | paragraph | ) |

Return the directionality of the text in the paragraph.

Parameters

  paragraph | the `pl_paragraph`

Returns
  `UBIDI_LTR` if the text is all left to right, `UBIDI_RTL` if the text is all right to left, or `UBIDI_MIXED` if the text has mixed direction.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunAscent()

U_CAPI le_int32 pl_getVisualRunAscent | ( | const pl_visualRun * | run | ) |

A convenience method which returns the ascent value for the font associated with this run.

Parameters

  run | the `pl_visualRun` object.

Returns
  the ascent value of this run's font.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunDescent()

U_CAPI le_int32 pl_getVisualRunDescent | ( | const pl_visualRun * | run | ) |

A convenience method which returns the descent value for the font associated with this run.

Parameters

  run | the `pl_visualRun` object.

Returns
  the descent value of this run's font.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunDirection()

U_CAPI UBiDiDirection pl_getVisualRunDirection | ( | const pl_visualRun * | run | ) |

Get the direction of the visual run.

Parameters

  run | the `pl_visualRun` object.

Returns
  the direction of the run. This will be `UBIDI_LTR` if the run is left-to-right and `UBIDI_RTL` if the line is right-to-left.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunFont()

U_CAPI const le_font* pl_getVisualRunFont | ( | const pl_visualRun * | run | ) |

Get the `le_font` object which represents the font of the visual run.

This will always be a non-composite font.

Parameters

  run | the `pl_visualRun` object.

Returns
  the `le_font` object which represents the font of the visual run.

See also
  le_font

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunGlyphCount()

U_CAPI le_int32 pl_getVisualRunGlyphCount | ( | const pl_visualRun * | run | ) |

Get the number of glyphs in the visual run.

Parameters

  run | the `pl_visualRun` object.

Returns
  the number of glyphs.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunGlyphs()

U_CAPI const LEGlyphID* pl_getVisualRunGlyphs | ( | const pl_visualRun * | run | ) |

Get the glyphs in the visual run.

Glyphs with the values `0xFFFE` and `0xFFFF` should be ignored.

Parameters

  run | the `pl_visualRun` object.

Returns
  the address of the array of glyphs for this visual run. The storage is owned by the `pl_visualRun` object and must not be deleted. It will remain valid as long as the `pl_visualRun` object is valid.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunGlyphToCharMap()

U_CAPI const le_int32* pl_getVisualRunGlyphToCharMap | ( | const pl_visualRun * | run | ) |

Get the glyph-to-character map for this visual run.

This maps the indices into the glyph array to indices into the character array used to create the paragraph.

Parameters

  run | the `pl_visualRun` object.

Returns
  the address of the character-to-glyph map for this visual run. The storage is owned by the `pl_visualRun` object and must not be deleted. It will remain valid as long as the `pl_visualRun` object is valid.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunLeading()

U_CAPI le_int32 pl_getVisualRunLeading | ( | const pl_visualRun * | run | ) |

A convenience method which returns the leading value for the font associated with this run.

Parameters

  run | the `pl_visualRun` object.

Returns
  the leading value of this run's font.

Internal:
  Do not use. This API is for internal use only.

## pl_getVisualRunPositions()

U_CAPI const float* pl_getVisualRunPositions | ( | const pl_visualRun * | run | ) |

Get the (x, y) positions of the glyphs in the visual run.

To simplify storage management, the x and y positions are stored in a single array with the x positions at even offsets in the array and the corresponding y position in the following odd offset. There is an extra (x, y) pair at the end of the array which represents the advance of the final glyph in the run.

Parameters

  run | the `pl_visualRun` object.

Returns
  the address of the array of glyph positions for this visual run. The storage is owned by the `pl_visualRun` object and must not be deleted. It will remain valid as long as the `pl_visualRun` object is valid.

Internal:
  Do not use. This API is for internal use only.

## pl_isComplex()

U_CAPI le_bool pl_isComplex | ( | const LEUnicode | chars[],
|  | le_int32 | count
| ) |  |

Examine the given text and determine if it contains characters in any script which requires complex processing to be rendered correctly.

Parameters

  chars | is an array of the characters in the paragraph
  count | is the number of characters in the paragraph.

Returns
  `true` if any of the text requires complex processing.

Internal:
  Do not use. This API is for internal use only.

## pl_nextLine()

U_CAPI pl_line* pl_nextLine | ( | pl_paragraph * | paragraph,
|  | float | width
| ) |  |

Return a `pl_line` object which represents next line in the paragraph.

The width of the line is specified each time so that it can be varied to support arbitrary paragraph shapes.

Parameters

  paragraph | the `pl_paragraph`
  width | is the width of the line. If `width` is less than or equal to zero, a `ParagraphLayout::Line` object representing the rest of the paragraph will be returned.

Returns
  a `ParagraphLayout::Line` object which represents the line. The caller is responsible for deleting the object. Returns `NULL` if there are no more lines in the paragraph.

See also
  pl_line

Internal:
  Do not use. This API is for internal use only.

## pl_reflow()

U_CAPI void pl_reflow | ( | pl_paragraph * | paragraph | ) |

Reset line breaking to start from the beginning of the paragraph.

Parameters

  paragraph | the `pl_paragraph`

Internal:
  Do not use. This API is for internal use only.