Portability | portable (depends on GHC) |
---|---|
Stability | provisional |
Maintainer | gtk2hs-users@lists.sourceforge.net |
Gtk specific functions to for redering with Cairo.
Cairo is a graphics library that supports vector graphics and image
compositing that can be used with Gdk.
The Cairo API is an addition to Gdk/Gtk (rather than a replacement).
Cairo rendering can be performed on any Graphics.UI.Gtk.Gdk.Drawable
by calling renderWithDrawable
. The functions in this module provide
ways of drawing Gtk specific elements, such as Pixbuf
s or text
laid out with Pango.
All functions in this module are only available in Gtk 2.8 or higher.
- cairoFontMapGetDefault :: IO FontMap
- cairoFontMapSetResolution :: FontMap -> Double -> IO ()
- cairoFontMapGetResolution :: FontMap -> IO Double
- cairoCreateContext :: Maybe FontMap -> IO PangoContext
- cairoContextSetResolution :: PangoContext -> Double -> IO ()
- cairoContextGetResolution :: PangoContext -> IO Double
- cairoContextSetFontOptions :: PangoContext -> FontOptions -> IO ()
- cairoContextGetFontOptions :: PangoContext -> IO FontOptions
- renderWithDrawable :: DrawableClass drawable => drawable -> Render a -> IO a
- setSourceColor :: Color -> Render ()
- setSourcePixbuf :: Pixbuf -> Double -> Double -> Render ()
- region :: Region -> Render ()
- updateContext :: PangoContext -> Render ()
- createLayout :: String -> Render PangoLayout
- updateLayout :: PangoLayout -> Render ()
- showGlyphString :: GlyphItem -> Render ()
- showLayoutLine :: LayoutLine -> Render ()
- showLayout :: PangoLayout -> Render ()
- glyphStringPath :: GlyphItem -> Render ()
- layoutLinePath :: LayoutLine -> Render ()
- layoutPath :: PangoLayout -> Render ()
Global Cairo settings.
cairoFontMapGetDefault :: IO FontMapSource
Retrieve the default Graphics.UI.Gtk.Pango.FontMap
that contains a
list of available fonts.
- One purpose of creating an explicit
Graphics.UI.Gtk.Pango.Font.FontMap
is to set a different scaling factor between font sizes (in points, pt) and Cairo units (in pixels). The default is 96dpi (dots per inch) which corresponds to an average screen as output medium. A 10pt font will therefore scale to10pt * (1/72 pt/inch) * (96 pixel/inch) = 13.3 pixel
.
cairoFontMapSetResolution :: FontMap -> Double -> IO ()Source
Set the scaling factor between font size and Cairo units.
- Value is in dots per inch (dpi). See
cairoFontMapNew
.
cairoFontMapGetResolution :: FontMap -> IO DoubleSource
Ask for the scaling factor between font size and Cairo units.
- Value is in dots per inch (dpi). See
cairoFontMapNew
.
cairoCreateContext :: Maybe FontMap -> IO PangoContextSource
Create a PangoContext
.
cairoContextSetResolution :: PangoContext -> Double -> IO ()Source
Set the scaling factor of the PangoContext
.
- Supplying zero or a negative value will result in the resolution value
of the underlying
FontMap
to be used. See alsocairoFontMapNew
.
cairoContextGetResolution :: PangoContext -> IO DoubleSource
Ask for the scaling factor of the PangoContext
.
- A negative value will be returned if no resolution has been set.
See
cairoContextSetResolution
.
cairoContextSetFontOptions :: PangoContext -> FontOptions -> IO ()Source
Set Cairo font options.
- Apply the given font options to the context. Values set through this
functions override those that are set by
updateContext
.
cairoContextGetFontOptions :: PangoContext -> IO FontOptionsSource
Retrieve Cairo font options.
Functions for the Render
monad.
:: DrawableClass drawable | |
=> drawable |
|
-> Render a | A newly created Cairo context. |
-> IO a |
Creates a Cairo context for drawing to a Drawable
.
setSourceColor :: Color -> Render ()Source
Sets the given pixbuf as the source pattern for the Cairo context. The
pattern has an extend mode of ExtendNone
and is aligned so that the
origin of pixbuf is (x, y)
.
updateContext :: PangoContext -> Render ()Source
Update a PangoContext
with respect to changes in a Render
environment.
- The
PangoContext
must have been created withcairoCreateContext
. AnyPangoLayout
s that have been previously created with this context have to be update usingGraphics.UI.Gtk.Pango.Layout.layoutContextChanged
.
createLayout :: String -> Render PangoLayoutSource
Create a PangoLayout
within a Render
context.
- This is a convenience function that creates a new
PangoContext
within thisRender
context and creates a newPangoLayout
. If the transformation or target surface of theRender
context change,updateLayout
has to be called on this layout.
updateLayout :: PangoLayout -> Render ()Source
Propagate changed to the Render
context to a PangoLayout
.
- This is a convenience function that calls
updateContext
on the (private)PangoContext
of the given layout to propagate changes from theRender
context to thePangoContext
and then callsGraphics.UI.Gtk.Pango.Layout.layoutContextChanged
on the layout. This function is necessary forcreateLayout
since a privatePangoContext
is created that is not visible to the user.
showGlyphString :: GlyphItem -> Render ()Source
Draw a glyph string.
- The origin of the glyphs (the left edge of the baseline) will be drawn at the current point of the cairo context.
showLayoutLine :: LayoutLine -> Render ()Source
Draw a LayoutLine
.
- The origin of the glyphs (the left edge of the baseline) will be drawn at the current point of the cairo context.
showLayout :: PangoLayout -> Render ()Source
Draw a PangoLayout
.
- The top-left corner of the
PangoLayout
will be drawn at the current point of the cairo context.
glyphStringPath :: GlyphItem -> Render ()Source
Add the extent of a glyph string to the current path.
- The origin of the glyphs (the left edge of the line) will be at the current point of the cairo context.
layoutLinePath :: LayoutLine -> Render ()Source
Add the extent of a layout line to the current path.
- The origin of the glyphs (the left edge of the line) will be at the current point of the cairo context.
layoutPath :: PangoLayout -> Render ()Source
Add the layout to the current path.
- Adds the top-left corner of the text to the current path. Afterwards,
the path position is at the bottom-right corner of the
PangoLayout
.