Portability | portable (depends on GHC) |
---|---|
Stability | provisional |
Maintainer | gtk2hs-users@lists.sourceforge.net |
Safe Haskell | None |
Functions to run the rendering pipeline.
- The
PangoLayout
object defined in this module contain a rendered paragraph of text. This interface is the easiest way to render text into aDrawWindow
using Cairo.
- data PangoRectangle = PangoRectangle Double Double Double Double
- data PangoLayout
- layoutEmpty :: PangoContext -> IO PangoLayout
- layoutText :: PangoContext -> String -> IO PangoLayout
- layoutCopy :: PangoLayout -> IO PangoLayout
- layoutGetContext :: PangoLayout -> IO PangoContext
- layoutContextChanged :: PangoLayout -> IO ()
- layoutSetText :: PangoLayout -> String -> IO ()
- layoutGetText :: PangoLayout -> IO String
- layoutSetMarkup :: PangoLayout -> Markup -> IO String
- escapeMarkup :: String -> String
- layoutSetMarkupWithAccel :: PangoLayout -> Markup -> IO (Char, String)
- layoutSetAttributes :: PangoLayout -> [PangoAttribute] -> IO ()
- layoutGetAttributes :: PangoLayout -> IO [[PangoAttribute]]
- layoutSetFontDescription :: PangoLayout -> Maybe FontDescription -> IO ()
- layoutGetFontDescription :: PangoLayout -> IO (Maybe FontDescription)
- layoutSetWidth :: PangoLayout -> Maybe Double -> IO ()
- layoutGetWidth :: PangoLayout -> IO (Maybe Double)
- data LayoutWrapMode
- layoutSetWrap :: PangoLayout -> LayoutWrapMode -> IO ()
- layoutGetWrap :: PangoLayout -> IO LayoutWrapMode
- data EllipsizeMode
- layoutSetEllipsize :: PangoLayout -> EllipsizeMode -> IO ()
- layoutGetEllipsize :: PangoLayout -> IO EllipsizeMode
- layoutSetIndent :: PangoLayout -> Double -> IO ()
- layoutGetIndent :: PangoLayout -> IO Double
- layoutSetSpacing :: PangoLayout -> Double -> IO ()
- layoutGetSpacing :: PangoLayout -> IO Double
- layoutSetJustify :: PangoLayout -> Bool -> IO ()
- layoutGetJustify :: PangoLayout -> IO Bool
- layoutSetAutoDir :: PangoLayout -> Bool -> IO ()
- layoutGetAutoDir :: PangoLayout -> IO Bool
- data LayoutAlignment
- = AlignLeft
- | AlignCenter
- | AlignRight
- layoutSetAlignment :: PangoLayout -> LayoutAlignment -> IO ()
- layoutGetAlignment :: PangoLayout -> IO LayoutAlignment
- data TabAlign
- type TabPosition = (Double, TabAlign)
- layoutSetTabs :: PangoLayout -> [TabPosition] -> IO ()
- layoutResetTabs :: PangoLayout -> IO ()
- layoutGetTabs :: PangoLayout -> IO (Maybe [TabPosition])
- layoutSetSingleParagraphMode :: PangoLayout -> Bool -> IO ()
- layoutGetSingleParagraphMode :: PangoLayout -> IO Bool
- layoutXYToIndex :: PangoLayout -> Double -> Double -> IO (Bool, Int, Int)
- layoutIndexToPos :: PangoLayout -> Int -> IO PangoRectangle
- layoutGetCursorPos :: PangoLayout -> Int -> IO (PangoRectangle, PangoRectangle)
- data CursorPos
- layoutMoveCursorVisually :: PangoLayout -> Bool -> Int -> Bool -> IO CursorPos
- layoutGetExtents :: PangoLayout -> IO (PangoRectangle, PangoRectangle)
- layoutGetPixelExtents :: PangoLayout -> IO (Rectangle, Rectangle)
- layoutGetLineCount :: PangoLayout -> IO Int
- layoutGetLine :: PangoLayout -> Int -> IO LayoutLine
- layoutGetLines :: PangoLayout -> IO [LayoutLine]
- data LayoutIter
- layoutGetIter :: PangoLayout -> IO LayoutIter
- layoutIterNextItem :: LayoutIter -> IO Bool
- layoutIterNextChar :: LayoutIter -> IO Bool
- layoutIterNextCluster :: LayoutIter -> IO Bool
- layoutIterNextLine :: LayoutIter -> IO Bool
- layoutIterAtLastLine :: LayoutIter -> IO Bool
- layoutIterGetIndex :: LayoutIter -> IO Int
- layoutIterGetBaseline :: LayoutIter -> IO Double
- layoutIterGetItem :: LayoutIter -> IO (Maybe GlyphItem)
- layoutIterGetLine :: LayoutIter -> IO (Maybe LayoutLine)
- layoutIterGetCharExtents :: LayoutIter -> IO PangoRectangle
- layoutIterGetClusterExtents :: LayoutIter -> IO (PangoRectangle, PangoRectangle)
- layoutIterGetRunExtents :: LayoutIter -> IO (PangoRectangle, PangoRectangle)
- layoutIterGetLineYRange :: LayoutIter -> IO (Double, Double)
- layoutIterGetLineExtents :: LayoutIter -> IO (PangoRectangle, PangoRectangle)
- data LayoutLine
- layoutLineGetExtents :: LayoutLine -> IO (PangoRectangle, PangoRectangle)
- layoutLineGetPixelExtents :: LayoutLine -> IO (Rectangle, Rectangle)
- layoutLineIndexToX :: LayoutLine -> Int -> Bool -> IO Double
- layoutLineXToIndex :: LayoutLine -> Double -> IO (Bool, Int, Int)
- layoutLineGetXRanges :: LayoutLine -> Int -> Int -> IO [(Double, Double)]
Documentation
data PangoRectangle Source
Rectangles describing an area in Double
s.
- Specifies x, y, width and height
data PangoLayout Source
A rendered paragraph.
layoutEmpty :: PangoContext -> IO PangoLayoutSource
Create an empty Layout
.
layoutText :: PangoContext -> String -> IO PangoLayoutSource
Create a new layout.
layoutCopy :: PangoLayout -> IO PangoLayoutSource
Create a copy of the Layout
.
layoutGetContext :: PangoLayout -> IO PangoContextSource
Retrieves the PangoContext
from this layout.
layoutContextChanged :: PangoLayout -> IO ()Source
Signal a PangoContext
change.
- Forces recomputation of any state in the
PangoLayout
that might depend on the layout's context. This function should be called if you make changes to the context subsequent to creating the layout.
layoutSetText :: PangoLayout -> String -> IO ()Source
Set the string in the layout.
layoutGetText :: PangoLayout -> IO StringSource
Retrieve the string in the layout.
layoutSetMarkup :: PangoLayout -> Markup -> IO StringSource
Set the text of the layout, including attributes.
The string may include Markup
. To print markup characters like
'<'
, or '-'
, apply escapeMarkup
to the string first.
The function returns the text that is actually shown.
escapeMarkup :: String -> StringSource
Escape markup characters.
- Used to display characters that normally denote markup. Note that this function is strict in that it forces all characters in the input string as soon as a single output character is requested.
layoutSetMarkupWithAccel :: PangoLayout -> Markup -> IO (Char, String)Source
Set the string in the layout.
- The string may include
Markup
. Furthermore, any underscore character indicates that the next character will be marked as accelerator (i.e. underlined). A literal underscore character can be produced by placing it twice in the string. - The character which follows the underscore is returned so it can be used to add the actual keyboard shortcut. The second element is the string after parsing.
layoutSetAttributes :: PangoLayout -> [PangoAttribute] -> IO ()Source
Set text attributes of the text in the layout.
- This function replaces any text attributes that this layout contained,
even those that were set by using
layoutSetMarkup
.
layoutGetAttributes :: PangoLayout -> IO [[PangoAttribute]]Source
Gets the list of attributes of the layout, if any.
- The attribute list is a list of lists of attribute. Each list describes the attributes for the same span.
layoutSetFontDescription :: PangoLayout -> Maybe FontDescription -> IO ()Source
Set a specific font description for this layout.
- Specifying
Nothing
will unset the current font description, that is, thePangoLayout
will use the font description in the currentPangoContext
.
layoutGetFontDescription :: PangoLayout -> IO (Maybe FontDescription)Source
Ask for the specifically set font description of this layout.
- Returns
Nothing
if this layout uses the font description in thePangoContext
it was created in. - Only available in Pango 1.8.0 or higher.
layoutSetWidth :: PangoLayout -> Maybe Double -> IO ()Source
Set the width of this paragraph.
- Sets the width to which the lines of the
PangoLayout
should be wrapped. - Pass in
Nothing
to indicate that no wrapping is to be performed.
layoutGetWidth :: PangoLayout -> IO (Maybe Double)Source
Gets the width of this paragraph.
- Gets the width to which the lines of the
PangoLayout
should be wrapped. - Returns is the current width, or
Nothing
to indicate that no wrapping is performed.
data LayoutWrapMode Source
Enumerates how a line can be wrapped.
WrapWholeWords
- Breaks lines only between words.
- This variant does not guarantee that the requested width is not exceeded. A word that is longer than the paragraph width is not split.
WrapAnywhere
- Break lines anywhere.
WrapPartialWords
- Wrap within a word if it is the only one on this line.
- This option acts like
WrapWholeWords
but will split a word if it is the only one on this line and it exceeds the specified width.
layoutSetWrap :: PangoLayout -> LayoutWrapMode -> IO ()Source
Set how this paragraph is wrapped.
- Sets the wrap style; the wrap style only has an effect if a width
is set on the layout with
layoutSetWidth
. To turn off wrapping, calllayoutSetWidth
withNothing
.
layoutGetWrap :: PangoLayout -> IO LayoutWrapModeSource
Get the wrap mode for the layout.
data EllipsizeMode Source
The EllipsizeMode
type describes what sort of (if any) ellipsization
should be applied to a line of text. In the ellipsization process characters
are removed from the text in order to make it fit to a given width and
replaced with an ellipsis.
layoutSetEllipsize :: PangoLayout -> EllipsizeMode -> IO ()Source
Set how long lines should be abbreviated.
layoutGetEllipsize :: PangoLayout -> IO EllipsizeModeSource
Get the ellipsize mode for this layout.
layoutSetIndent :: PangoLayout -> Double -> IO ()Source
Set the indentation of this paragraph.
- Sets the amount by which the first line should be indented. A negative value will produce a hanging indent, that is, all subsequent lines will be indented while the first line has full width.
layoutGetIndent :: PangoLayout -> IO DoubleSource
Gets the indentation of this paragraph.
- Gets the amount by which the first line or the rest of the paragraph is indented.
layoutSetSpacing :: PangoLayout -> Double -> IO ()Source
Set the spacing between lines of this paragraph.
layoutGetSpacing :: PangoLayout -> IO DoubleSource
Gets the spacing between the lines.
layoutSetJustify :: PangoLayout -> Bool -> IO ()Source
Set if text should be streched to fit width.
- Sets whether or not each complete line should be stretched to fill the entire width of the layout. This stretching is typically done by adding whitespace, but for some scripts (such as Arabic), the justification is done by extending the characters.
- Note that as of Pango 1.4, this functionality is not yet implemented.
layoutGetJustify :: PangoLayout -> IO BoolSource
Retrieve the justification flag.
- See
layoutSetJustify
.
layoutSetAutoDir :: PangoLayout -> Bool -> IO ()Source
Set if the base text direction should be overridden.
- Sets whether to calculate the bidirectional base direction for the layout according to the contents of the layout; when this flag is on (the default), then paragraphs in layout that begin with strong right-to-left characters (Arabic and Hebrew principally), will have right-to-left layout, paragraphs with letters from other scripts will have left-to-right layout. Paragraphs with only neutral characters get their direction from the surrounding paragraphs.
- When
False
, the choice between left-to-right and right-to-left layout is done by according to the base direction of the layout'sPangoContext
. (SeecontextSetTextDir
). - When the auto-computed direction or a paragraph differs from the base
direction of the context, then the interpretation of
AlignLeft
andAlignRight
are swapped.
layoutGetAutoDir :: PangoLayout -> IO BoolSource
Retrieve the auto direction flag.
- See
layoutSetAutoDir
.
data LayoutAlignment Source
Enumerate to which side incomplete lines are flushed.
layoutSetAlignment :: PangoLayout -> LayoutAlignment -> IO ()Source
Set how this paragraph is aligned.
- Sets the alignment for the layout (how partial lines are positioned within the horizontal space available.)
layoutGetAlignment :: PangoLayout -> IO LayoutAlignmentSource
Get the alignment for the layout.
Specify where the Tab stop appears relative to the text.
- Only Tab stops that align text to the left are supported right now.
type TabPosition = (Double, TabAlign)Source
A Tab position.
layoutSetTabs :: PangoLayout -> [TabPosition] -> IO ()Source
Set a list of Tab positoins.
layoutResetTabs :: PangoLayout -> IO ()Source
Reset the original set of Tab positions.
- Restore the default which is a Tab stop every eight characters.
layoutGetTabs :: PangoLayout -> IO (Maybe [TabPosition])Source
Retrieve the list of current Tab positions.
- If no Tab position where set,
Nothing
is returned. In this case, Tab positions are implicit at every eight characters.
layoutSetSingleParagraphMode :: PangoLayout -> Bool -> IO ()Source
Honor newlines or not.
- If
honor
isTrue
, do not treat newlines and similar characters as paragraph separators; instead, keep all text in a single paragraph, and display a glyph for paragraph separator characters. Used when you want to allow editing of newlines on a single text line.
layoutGetSingleParagraphMode :: PangoLayout -> IO BoolSource
Retrieve if newlines are honored.
Converts a device unit to a character index.
- Converts from
x
andy
position within a layout to the index of the closest character. If they
position is not inside the layout, the closest position is chosen (the position will be clamped inside the layout). If thex
position is not within the layout, then the start or the end of the line is chosen. If either thex
ory
positions were not inside the layout, then the function returnsFalse
; on an exact hit, it returnsTrue
. - The function returns the flag for the exact hit and the index into the string. The third value is zero if the character corresponds to one grapheme. If the grapheme is the result of a cluster, this value may be greater than one, indicating where in the grapheme the position lies. Zero represents the trailing edge on the grapheme.
layoutIndexToPos :: PangoLayout -> Int -> IO PangoRectangleSource
Return the rectangle of the glyph at the given index.
- Converts from an index within a
PangoLayout
to the onscreen position corresponding to the grapheme at that index, which is represented as rectangle. Note that, given aPangoRectangle x y width height
,x
is always the leading edge of the grapheme andx + width
the trailing edge of the grapheme. If the directionality of the grapheme is right-to-left, thenwidth
will be negative.
:: PangoLayout | |
-> Int | |
-> IO (PangoRectangle, PangoRectangle) | (strong, weak) |
Return a cursor position.
- Given an index within a layout, determines the positions that of the strong and weak cursors if the insertion point is at that index. The position of each cursor is stored as a zero-width rectangle. The strong cursor location is the location where characters of the directionality equal to the base direction of the layout are inserted. The weak cursor location is the location where characters of the directionality opposite to the base direction of the layout are inserted. The first element of the typle is the strong position, the second the weak.
A new cursor position.
CursorPosPrevPara | The cursor should move to the previous paragraph. |
CursorPos Int Int | The sum of the indices is the new cursor position. |
CursorPosNextPara | The cursor should advance to the next paragraph. |
layoutMoveCursorVisuallySource
:: PangoLayout | |
-> Bool |
|
-> Int | The previous position. |
-> Bool |
|
-> IO CursorPos |
Move a cursor visually.
- Compute a new cursor position from a previous cursor position. A value
of
True
for the direction will move it to the right, independant of the underlying direction. Hence the cursor position might jump if left-to-right text is mixed with right-to-left text. - The first flag should be
True
if this cursor is the strong cursor. The strong cursor is the cursor of the base direction of the current layout (seelayoutSetAutoDir
). The weak cursor is that of the opposite direction. - The previous cursor position is given by
idx
. If this text at this position is a cluster, the cursor will only move to the end or beginning of the cluster as opposed to past the next character. The return value is eitherCursorPosNextPara
if the cursor moved beyond this paragraph, it isCursorPosPrevPara
if the cursor moved in front of this paragraph and it isCursorPos
idx
trail
to denote the new cursor positionidx
. Note thatidx
will always denote an insertion point, that is,idx
will never point into the middle of a cluster. Thetrail
value can contain a positive value if the current cursor position is at the end of the current line. In this case,idx
points past the last character of this line whiletrail
contains the number of characters that are reponsible for the line break such as newlines. The actual cursor position is alwaysidx+trail
where the visual cursor should be shown.
:: PangoLayout | |
-> IO (PangoRectangle, PangoRectangle) | (ink, logical) |
Computes the logical and ink extents of the PangoLayout
.
Logical extents are usually what you want for positioning things. Note that both extents may have non-zero x and y. You may want to use those to offset where you render the layout. Not doing that is a very typical bug that shows up as right-to-left layouts not being correctly positioned in a layout with a set width.
Layout coordinates begin at the top left corner of the layout.
:: PangoLayout | |
-> IO (Rectangle, Rectangle) | (ink, logical) |
Compute the physical size of the layout.
- Computes the ink and the logical size of the
Layout
in device units, that is, pixels for a screen. Identical tolayoutGetExtents
and converting theDouble
s in thePangoRectangle
to integers.
layoutGetLineCount :: PangoLayout -> IO IntSource
Ask for the number of lines in this layout.
layoutGetLine :: PangoLayout -> Int -> IO LayoutLineSource
Extract a single lines of the layout.
- The given index starts from 0. The function throws an
ArrayException
if the index is out of bounds. - The lines of each layout are regenerated if any attribute changes. Thus the returned list does not reflect the current state of lines after a change has been made.
layoutGetLines :: PangoLayout -> IO [LayoutLine]Source
Extract the lines of the layout.
- The lines of each layout are regenerated if any attribute changes. Thus the returned list does not reflect the current state of lines after a change has been made.
data LayoutIter Source
An iterator to examine a layout.
layoutGetIter :: PangoLayout -> IO LayoutIterSource
Create an iterator to examine a layout.
layoutIterNextItem :: LayoutIter -> IO BoolSource
Move to the next GlyphItem
.
- Returns
False
if this was the last item in the layout.
layoutIterNextChar :: LayoutIter -> IO BoolSource
Move to the next char.
- Returns
False
if this was the last char in the layout.
layoutIterNextCluster :: LayoutIter -> IO BoolSource
Move to the next cluster.
- Returns
False
if this was the last cluster in the layout.
layoutIterNextLine :: LayoutIter -> IO BoolSource
Move to the next line.
- Returns
False
if this was the last line in the layout.
layoutIterAtLastLine :: LayoutIter -> IO BoolSource
Check if the iterator is on the last line.
- Returns
True
if the iterator is on the last line of this paragraph.
layoutIterGetIndex :: LayoutIter -> IO IntSource
Get the character index.
- Note that iterating forward by char moves in visual order, not logical order, so indexes may not be sequential. Also, the index may be equal to the length of the text in the layout.
layoutIterGetBaseline :: LayoutIter -> IO DoubleSource
Query the vertical position within the layout.
- Gets the y position of the current line's baseline (origin at top left of the entire layout).
layoutIterGetItem :: LayoutIter -> IO (Maybe GlyphItem)Source
Retrieve the current GlyphItem
under the iterator.
- Each
LayoutLine
contains a list ofGlyphItem
s. This function returns theGlyphItem
under the current iterator. If the iterator is positioned past the last charactor of the paragraph, the function returnsNothing
.
layoutIterGetLine :: LayoutIter -> IO (Maybe LayoutLine)Source
Extract the line under the iterator.
layoutIterGetCharExtents :: LayoutIter -> IO PangoRectangleSource
Retrieve a rectangle surrounding a character.
- Get the extents of the current character (origin is the top left of the entire layout). Only logical extents can sensibly be obtained for characters; ink extents make sense only down to the level of clusters.
layoutIterGetClusterExtentsSource
:: LayoutIter | |
-> IO (PangoRectangle, PangoRectangle) | (ink, logical) |
Compute the physical size of the cluster.
- Computes the ink and the logical size of the cluster pointed to by
LayoutIter
.
layoutIterGetRunExtents :: LayoutIter -> IO (PangoRectangle, PangoRectangle)Source
Compute the physical size of the run.
- Computes the ink and the logical size of the run pointed to by
LayoutIter
.
layoutIterGetLineYRange :: LayoutIter -> IO (Double, Double)Source
Retrieve vertical extent of this line.
- Divides the vertical space in the
PangoLayout
being iterated over between the lines in the layout, and returns the space belonging to the current line. A line's range includes the line's logical extents, plus half of the spacing above and below the line, iflayoutSetSpacing
has been called to set layout spacing. The y positions are in layout coordinates (origin at top left of the entire layout). - The first element in the returned tuple is the start, the second is the end of this line.
layoutIterGetLineExtents :: LayoutIter -> IO (PangoRectangle, PangoRectangle)Source
Compute the physical size of the line.
- Computes the ink and the logical size of the line pointed to by
LayoutIter
. SeelayoutGetExtents
. - Extents are in layout coordinates (origin is the top-left corner
of the entire
PangoLayout
). Thus the extents returned by this function will be the same width/height but not at the same x/y as the extents returned fromlayoutLineGetExtents
.
data LayoutLine Source
A single line in a PangoLayout
.
layoutLineGetExtents :: LayoutLine -> IO (PangoRectangle, PangoRectangle)Source
Compute the physical size of the line.
- Computes the ink and the logical size of the
LayoutLine
. SeelayoutGetExtents
.
layoutLineGetPixelExtentsSource
:: LayoutLine | |
-> IO (Rectangle, Rectangle) | (ink, logical) |
Compute the physical size of the line.
- Computes the ink and the logical size of the
LayoutLine
. SeelayoutGetExtents
. The returned values are in device units, that is, pixels for the screen and points for printers.
:: LayoutLine | |
-> Int | the index into the string |
-> Bool | return the beginning ( |
-> IO Double |
Request the horizontal position of a character.
Request the character index of a given horizontal position.
- Converts from an x offset to the index of the corresponding
character within the text of the layout. If the
x
parameter is outside the line, a triple(False, index, trailing)
is returned whereindex
andtrailing
will point to the very first or very last position in the line. This notion of first and last position is based on the direction of the paragraph; for example, if the direction is right-to-left, then anx
position to the right of the line results in 0 being returned forindex
andtrailing
. Anx
position to the left of the line results inindex
pointing to the (logical) last grapheme in the line and trailing pointing to the number of characters in that grapheme. The reverse is true for a left-to-right line. If the boolean flag in the result isTrue
thenx
was within the layout line andtrailing
indicates where in a cluster thex
position lay. It is 0 for the trailing edge of the cluster.
:: LayoutLine | The line of interest. |
-> Int | The index of the start character (counting from 0). If this value is less than the start index for the line, then the first range will extend all the way to the leading edge of the layout. Otherwise it will start at the leading edge of the first character. |
-> Int | The index after the last character. If this value is greater than the end index for the line, then the last range will extend all the way to the trailing edge of the layout. Otherwise, it will end at the trailing edge of the last character. |
-> IO [(Double, Double)] |
Retrieve bounding boxes for a given piece of text contained in this
LayoutLine
.
- The result is a list to accommodate for mixed left-to-right and right-to-left text. Even if the text is not mixed, several ranges might be returned that are adjacent. The ranges are always sorted from left to right. The values are with respect to the left edge of the entire layout, not with respect to the line (which might be indented or not left aligned).