RasterSource

The raster source provides the ability to supply arbitrary pixel data whilst rendering. The pixels are queried at the time of rasterisation by means of user callback functions, allowing for the ultimate flexibility. For example, in handling compressed image sources, you may keep a MRU cache of decompressed images and decompress sources on the fly and discard old ones to conserve memory.

For the raster source to be effective, you must at least specify the acquire and release callbacks which are used to retrieve the pixel data for the region of interest and demark when it can be freed afterwards. Other callbacks are provided for when the pattern is copied temporarily during rasterisation, or more permanently as a snapshot in order to keep the pixel data available for printing.

class RasterSource : Pattern {

protected

cairo_pattern_t* cairo_pattern;

cairo_pattern_t* getRasterSourceStruct();

void* getStruct();

this(cairo_pattern_t* cairo_pattern);

this(void* userData, CairoContent content, int width, int height);

void setCallbackData(void* data);

void* getCallbackData();

void setAcquire(cairo_raster_source_acquire_func_t acquire, cairo_raster_source_release_func_t release);

void getAcquire(cairo_raster_source_acquire_func_t* acquire, cairo_raster_source_release_func_t* release);

void setSnapshot(cairo_raster_source_snapshot_func_t snapshot);

cairo_raster_source_snapshot_func_t getSnapshot();

void setCopy(cairo_raster_source_copy_func_t copy);

cairo_raster_source_copy_func_t getCopy();

void setFinish(cairo_raster_source_finish_func_t finish);

cairo_raster_source_finish_func_t getFinish();

}

Constructors

this this(cairo_pattern_t* cairo_pattern): Sets our main struct and passes it to the parent class
this this(void* userData, CairoContent content, int width, int height): Creates a new user pattern for providing pixel data.

Members

Functions

getAcquire void getAcquire(cairo_raster_source_acquire_func_t* acquire, cairo_raster_source_release_func_t* release): Queries the current acquire and release callbacks. Since 1.12
getCallbackData void* getCallbackData(): Queries the current user data. Since 1.12
getCopy cairo_raster_source_copy_func_t getCopy(): Queries the current copy callback. Since 1.12
getFinish cairo_raster_source_finish_func_t getFinish(): Queries the current finish callback. Since 1.12
getRasterSourceStruct cairo_pattern_t* getRasterSourceStruct(): Get the main Gtk struct
getSnapshot cairo_raster_source_snapshot_func_t getSnapshot(): Queries the current snapshot callback. Since 1.12
getStruct void* getStruct(): the main Gtk struct as a void*
setAcquire void setAcquire(cairo_raster_source_acquire_func_t acquire, cairo_raster_source_release_func_t release): Specifies the callbacks used to generate the image surface for a rendering operation (acquire) and the function used to cleanup that surface afterwards. The acquire callback should create a surface (preferably an image surface created to match the target using Surface.createSimilarImage) that defines at least the region of interest specified by extents. The surface is allowed to be the entire sample area, but if it does contain a subsection of the sample area, the surface extents should be provided by setting the device offset (along with its width and height) using Surface.setDeviceOffset. Since 1.12
setCallbackData void setCallbackData(void* data): Updates the user data that is provided to all callbacks. Since 1.12
setCopy void setCopy(cairo_raster_source_copy_func_t copy): Updates the copy callback which is used whenever a temporary copy of the pattern is taken. Since 1.12
setFinish void setFinish(cairo_raster_source_finish_func_t finish): Updates the finish callback which is used whenever a pattern (or a copy thereof) will no longer be used. Since 1.12
setSnapshot void setSnapshot(cairo_raster_source_snapshot_func_t snapshot): Sets the callback that will be used whenever a snapshot is taken of the pattern, that is whenever the current contents of the pattern should be preserved for later use. This is typically invoked whilst printing. Since 1.12

Variables

cairo_pattern cairo_pattern_t* cairo_pattern;: the main Gtk struct

Inherited Members

From Pattern

cairo_pattern cairo_pattern_t* cairo_pattern;: the main Gtk struct
getPatternStruct cairo_pattern_t* getPatternStruct(): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
addColorStopRgb void addColorStopRgb(double offset, double red, double green, double blue): Adds an opaque color stop to a gradient pattern. The offset specifies the location along the gradient's control vector. For example, a linear gradient's control vector is from (x0,y0) to (x1,y1) while a radial gradient's control vector is from any point on the start circle to the corresponding point on the end circle. The color is specified in the same way as in cairo_set_source_rgb(). If two (or more) stops are specified with identical offset values, they will be sorted according to the order in which the stops are added, (stops added earlier will compare less than stops added later). This can be useful for reliably making sharp color transitions instead of the typical blend. Note: If the pattern is not a gradient pattern, (eg. a linear or radial pattern), then the pattern will be put into an error status with a status of CAIRO_STATUS_PATTERN_TYPE_MISMATCH. Since 1.0
addColorStopRgba void addColorStopRgba(double offset, double red, double green, double blue, double alpha): Adds a translucent color stop to a gradient pattern. The offset specifies the location along the gradient's control vector. For example, a linear gradient's control vector is from (x0,y0) to (x1,y1) while a radial gradient's control vector is from any point on the start circle to the corresponding point on the end circle. The color is specified in the same way as in cairo_set_source_rgba(). If two (or more) stops are specified with identical offset values, they will be sorted according to the order in which the stops are added, (stops added earlier will compare less than stops added later). This can be useful for reliably making sharp color transitions instead of the typical blend. Note: If the pattern is not a gradient pattern, (eg. a linear or radial pattern), then the pattern will be put into an error status with a status of CAIRO_STATUS_PATTERN_TYPE_MISMATCH. Since 1.0
getColorStopCount cairo_status_t getColorStopCount(int count): Gets the number of color stops specified in the given gradient pattern. Since 1.4
getColorStopRgba cairo_status_t getColorStopRgba(int index, double offset, double red, double green, double blue, double alpha): Gets the color and offset information at the given index for a gradient pattern. Values of index are 0 to 1 less than the number returned by Pattern.getColorStopCount. Since 1.4
createRgb Pattern createRgb(double red, double green, double blue): Creates a new cairo_pattern_t corresponding to an opaque color. The color components are floating point numbers in the range 0 to 1. If the values passed in are outside that range, they will be clamped. Since 1.0
createRgba Pattern createRgba(double red, double green, double blue, double alpha): Creates a new cairo_pattern_t corresponding to a translucent color. The color components are floating point numbers in the range 0 to 1. If the values passed in are outside that range, they will be clamped. Since 1.0
getRgba cairo_status_t getRgba(double red, double green, double blue, double alpha): Gets the solid color for a solid color pattern. Since 1.4
createForSurface Pattern createForSurface(Surface surface): Create a new cairo_pattern_t for the given surface. Since 1.0
getSurface cairo_status_t getSurface(Surface surface): Gets the surface of a surface pattern. The reference returned in surface is owned by the pattern; the caller should call Surface.reference if the surface is to be retained. Since 1.4
createLinear Pattern createLinear(double x0, double y0, double x1, double y1): Create a new linear gradient cairo_pattern_t along the line defined by (x0, y0) and (x1, y1). Before using the gradient pattern, a number of color stops should be defined using Pattern.addColorStopRgb or Pattern.addColorStopRgba. Note: The coordinates here are in pattern space. For a new pattern, pattern space is identical to user space, but the relationship between the spaces can be changed with Pattern.setMatrix. Since 1.0
getLinearPoints cairo_status_t getLinearPoints(double x0, double y0, double x1, double y1): Gets the gradient endpoints for a linear gradient. Since 1.4
createRadial Pattern createRadial(double cx0, double cy0, double radius0, double cx1, double cy1, double radius1): Creates a new radial gradient cairo_pattern_t between the two circles defined by (cx0, cy0, radius0) and (cx1, cy1, radius1). Before using the gradient pattern, a number of color stops should be defined using Pattern.addColorStopRgb or Pattern.addColorStopRgba. Note: The coordinates here are in pattern space. For a new pattern, pattern space is identical to user space, but the relationship between the spaces can be changed with Pattern.setMatrix. Since 1.0
getRadialCircles cairo_status_t getRadialCircles(double x0, double y0, double r0, double x1, double y1, double r1): Gets the gradient endpoint circles for a radial gradient, each specified as a center coordinate and a radius. Since 1.4
reference Pattern reference(): Increases the reference count on pattern by one. This prevents pattern from being destroyed until a matching call to Pattern.destroy is made. The number of references to a cairo_pattern_t can be get using Pattern.getReferenceCount. Since 1.0
destroy void destroy(): Decreases the reference count on pattern by one. If the result is zero, then pattern and all associated resources are freed. See Pattern.reference. Since 1.0
status cairo_status_t status(): Checks whether an error has previously occurred for this pattern. Since 1.0
setExtend void setExtend(cairo_extend_t extend): Sets the mode to be used for drawing outside the area of a pattern. See cairo_extend_t for details on the semantics of each extend strategy. The default extend mode is CAIRO_EXTEND_NONE for surface patterns and CAIRO_EXTEND_PAD for gradient patterns. Since 1.0
getExtend cairo_extend_t getExtend(): Gets the current extend mode for a pattern. See cairo_extend_t for details on the semantics of each extend strategy. Since 1.0
setFilter void setFilter(cairo_filter_t filter): Sets the filter to be used for resizing when using this pattern. See cairo_filter_t for details on each filter. * Note that you might want to control filtering even when you do not have an explicit cairo_pattern_t object, (for example when using cairo_set_source_surface()). In these cases, it is convenient to use cairo_get_source() to get access to the pattern that cairo Since 1.0
getFilter cairo_filter_t getFilter(): Gets the current filter for a pattern. See cairo_filter_t for details on each filter. Since 1.0
setMatrix void setMatrix(Matrix matrix): Sets the pattern's transformation matrix to matrix. This matrix is a transformation from user space to pattern space. When a pattern is first created it always has the identity matrix for its transformation matrix, which means that pattern space is initially identical to user space. Important: Please note that the direction of this transformation matrix is from user space to pattern space. This means that if you imagine the flow from a pattern to user space (and on to device space), then coordinates in that flow will be transformed by the inverse of the pattern matrix. For example, if you want to make a pattern appear twice as large as Since 1.0
getMatrix void getMatrix(Matrix matrix): Stores the pattern's transformation matrix into matrix. Since 1.0
getType cairo_pattern_type_t getType(): This function returns the type a pattern. See cairo_pattern_type_t for available types. Since 1.2
getReferenceCount uint getReferenceCount(): Returns the current reference count of pattern. Since 1.4
setUserData cairo_status_t setUserData(cairo_user_data_key_t* key, void* userData, cairo_destroy_func_t destroy): Attach user data to pattern. To remove user data from a surface, call this function with the key that was used to set it and NULL for data. Since 1.4
getUserData void* getUserData(cairo_user_data_key_t* key): Return user data previously attached to pattern using the specified key. If no user data has been attached with the given key this function returns NULL. Since 1.4

cairo RasterSource classes

RasterSource