ImageSurface

Image Surfaces — Rendering to memory buffers

Image surfaces provide the ability to render to memory buffers either allocated by cairo or by the calling code. The supported image formats are those defined in Format.

class ImageSurface : Surface {

this(cairo_surface_t* ptr);

this(Format format, int width, int height);

this(ubyte[] data, Format format, int width, int height, int stride);

ubyte* getData();

alias data = getData;

Format getFormat();

alias format = getFormat;

int getWidth();

alias width = getWidth;

int getHeight();

alias height = getHeight;

int getStride();

alias stride = getStride;

version(D_Ddoc)

static ImageSurface fromPng(string file);

version(D_Ddoc)

void writeToPNG(string file);

}

Constructors

this this(cairo_surface_t* ptr): Create a ImageSurface from a existing cairo_surface_t*. ImageSurface is a garbage collected class. It will call cairo_surface_destroy when it gets collected by the GC or when dispose() is called.
this this(Format format, int width, int height): Creates an image surface of the specified format and dimensions. Initially the surface contents are all 0. (Specifically, within each pixel, each color or alpha channel belonging to format will be 0. The contents of bits within a pixel, but not belonging to the given format are undefined).
this this(ubyte[] data, Format format, int width, int height, int stride): Creates an image surface for the provided pixel data. The output buffer must be kept around until the Surface is destroyed or Surface.finish() is called on the surface. The initial contents of data will be used as the initial image contents; you must explicitly clear the buffer, using, for example, Context.rectangle() and Context.fill() if you want it cleared.

Members

Aliases

data alias data = getData: convenience alias
format alias format = getFormat: convenience alias
height alias height = getHeight: convenience alias
stride alias stride = getStride: convenience alias
width alias width = getWidth: convenience alias

Functions

getData ubyte* getData(): Get a pointer to the data of the image surface, for direct inspection or modification.
getFormat Format getFormat(): Get the format of the surface.
getHeight int getHeight(): Get the height of the image surface in pixels.
getStride int getStride(): Get the stride of the image surface in bytes.
getWidth int getWidth(): Get the width of the image surface in pixels.
writeToPNG void writeToPNG(string file): Writes the contents of surface to a new file filename as a PNG image.

Static functions

fromPng ImageSurface fromPng(string file): Creates a new image surface and initializes the contents to the given PNG file.

Inherited Members

From Surface

__anonymous mixin CairoCountedClass!(cairo_surface_t*, "cairo_surface_")
checkError void checkError(): Method for use in subclasses. Calls cairo_surface_status(nativePointer) and throws an exception if the status isn't CAIRO_STATUS_SUCCESS
createFromNative Surface createFromNative(cairo_surface_t* ptr, bool adjRefCount): The createFromNative method for the Surface classes. See https://github.com/jpf91/cairoD/wiki/Memory-Management#createFromNative for more information.
createSimilar Surface createSimilar(Surface other, Content content, int width, int height): Create a new surface that is as compatible as possible with an existing surface. For example the new surface will have the same fallback resolution and font options as other. Generally, the new surface will also use the same backend as other, unless that is not possible for some reason. The type of the returned surface may be examined with Surface.getType().
createForRectangle Surface createForRectangle(Surface target, Rectangle!double rect): Create a new surface that is a rectangle within the target surface. All operations drawn to this surface are then clipped and translated onto the target surface. Nothing drawn via this sub-surface outside of its bounds is drawn onto the target surface, making this a useful method for passing constrained child surfaces to library routines that draw directly onto the parent surface, i.e. with no further backend allocations, double buffering or copies.
finish void finish(): This function finishes the surface and drops all references to external resources. For example, for the Xlib backend it means that cairo will no longer access the drawable, which can be freed. After calling Surface.finish() the only valid operations on a surface are getting and setting user, referencing and destroying, and flushing and finishing it.
flush void flush(): Do any pending drawing for the surface and also restore any temporary modifications cairo has made to the surface's state. This function must be called before switching from drawing on the surface with cairo to drawing on it directly with native APIs. If the surface doesn't support direct access, then this function does nothing.
getDevice Device getDevice(): This function returns the device for a surface. See Device.
device alias device = getDevice: Convenience alias
getFontOptions FontOptions getFontOptions(): Retrieves the default font rendering options for the surface. This allows display surfaces to report the correct subpixel order for rendering on them, print surfaces to disable hinting of metrics and so forth. The result can then be used with $(new ScaledFont()).
fontOptions alias fontOptions = getFontOptions: Convenience alias
getContent Content getContent(): This function returns the content type of surface which indicates whether the surface contains color and/or alpha information. See Content.
content alias content = getContent: Convenience alias
markDirty void markDirty(): Tells cairo that drawing has been done to surface using means other than cairo, and that cairo should reread any cached areas. Note that you must call Surface.flush() before doing such drawing.
markDirtyRectangle void markDirtyRectangle(int x, int y, int width, int height)
void markDirtyRectangle(Rectangle!int rect): Like Surface.markDirty(), but drawing has been done only to the specified rectangle, so that cairo can retain cached contents for other parts of the surface.
setDeviceOffset void setDeviceOffset(double x_offset, double y_offset)
void setDeviceOffset(Point!double offset): Sets an offset that is added to the device coordinates determined by the CTM when drawing to surface. One use case for this function is when we want to create a Surface that redirects drawing for a portion of an onscreen surface to an offscreen surface in a way that is completely invisible to the user of the cairo API. Setting a transformation via Context.translate() isn't sufficient to do this, since functions like Context.deviceToUser() will expose the hidden offset.
getDeviceOffset Point!double getDeviceOffset(): This function returns the previous device offset set by Surface.setDeviceOffset().
deviceOffset Point!double deviceOffset [@property setter]
Point!double deviceOffset [@property getter]: Convenience property function ditto
setFallbackResolution void setFallbackResolution(Resolution res): Set the horizontal and vertical resolution for image fallbacks.
getFallbackResolution Resolution getFallbackResolution(): This function returns the previous fallback resolution set by setFallbackResolution(), or default fallback resolution if never set.
fallbackResolution Resolution fallbackResolution [@property setter]
Resolution fallbackResolution [@property getter]: Convenience property function
getType SurfaceType getType(): This function returns the C type of a Surface. See SurfaceType for available types.
type alias type = getType: convenience alias
copyPage void copyPage(): Emits the current page for backends that support multiple pages, but doesn't clear it, so that the contents of the current page will be retained for the next page. Use Surface.showPage() if you want to get an empty page after the emission.
showPage void showPage(): Emits and clears the current page for backends that support multiple pages. Use Surface.copyPage() if you don't want to clear the page.
hasShowTextGlyphs bool hasShowTextGlyphs(): Returns whether the surface supports sophisticated showTextGlyphs() operations. That is, whether it actually uses the provided text and cluster data to a showTextGlyphs() call.
setMimeData void setMimeData(string type, ubyte* data, ulong length, cairo_destroy_func_t destroy, void* closure): Attach an image in the format mime_type to surface. To remove the data from a surface, call this function with same mime type and NULL for data.
getMimeData void getMimeData(string type, ubyte* data, ulong length): Return mime data previously attached to surface using the specified mime type. If no data has been attached with the given mime type, data is set null.

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