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/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#include "cairo.h"
#include <X11/Xlib.h>
* This callback encapsulates Xlib-based rendering. We assume that the
* execution of the callback is equivalent to compositing some RGBA image of
* size (bounds_width, bounds_height) onto the drawable at offset (offset_x,
* offset_y), clipped to the union of the clip_rects if num_rects is greater
* than zero. This includes the assumption that the same RGBA image
* is composited if you call the callback multiple times with the same closure,
* display and visual during a single cairo_draw_with_xlib call.
* @return True on success, False on non-recoverable error
typedef cairo_bool_t (*cairo_xlib_drawing_callback)(
void* closure, Screen* screen, Drawable drawable, Visual* visual,
short offset_x, short offset_y, XRectangle* clip_rects,
unsigned int num_rects);
* This structure captures the result of the native drawing, in case the
* caller may wish to reapply the drawing efficiently later.
typedef struct {
cairo_surface_t* surface;
cairo_bool_t uniform_alpha;
cairo_bool_t uniform_color;
double alpha; /* valid only if uniform_alpha is TRUE */
double r, g, b; /* valid only if uniform_color is TRUE */
} cairo_xlib_drawing_result_t;
* This type specifies whether the native drawing callback draws all pixels
* in its bounds opaquely, independent of the contents of the target drawable,
* or whether it leaves pixels transparent/translucent or depends on the
* existing contents of the target drawable in some way.
typedef enum _cairo_xlib_drawing_opacity {
} cairo_xlib_drawing_opacity_t;
* This type encodes the capabilities of the native drawing callback.
* If CAIRO_XLIB_DRAWING_SUPPORTS_OFFSET is set, 'offset_x' and 'offset_y'
* can be nonzero in the call to the callback; otherwise they will be zero.
* If CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_RECT is set, then 'num_rects' can be
* zero or one in the call to the callback. If
* CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_LIST is set, then 'num_rects' can be
* anything in the call to the callback. Otherwise 'num_rects' will be zero.
* Do not set both of these values.
* be any screen on any display, otherwise it will be the default screen of
* the display passed into cairo_draw_with_xlib.
* any visual, otherwise it will be equal to
* DefaultVisualOfScreen (screen).
typedef enum {
} cairo_xlib_drawing_support_t;
* Draw Xlib output into any cairo context. All cairo transforms and effects
* are honored, including the current operator. This is equivalent to a
* cairo_set_source_surface and then cairo_paint.
* @param cr the context to draw into
* @param callback the code to perform Xlib rendering
* @param closure associated data
* @param dpy an X display to use in case the cairo context has no associated X
* display
* @param width the width of the putative image drawn by the callback
* @param height the height of the putative image drawn by the callback
* @param is_opaque set to CAIRO_XLIB_DRAWING_IS_OPAQUE to indicate
* that all alpha values of the putative image will be 1.0; the pixels drawn
* into the Drawable must not depend on the prior contents of the Drawable in
* any way
* @param capabilities the capabilities of the callback as described above.
* @param result if non-NULL, we *may* fill in the struct with information about
* the rendered image. 'surface' may be filled in with a surface representing
* the image, similar to the target of 'cr'. If 'uniform_alpha' is True then
* every pixel of the image has the same alpha value 'alpha'. If
* 'uniform_color' is True then every pixel of the image has the same RGB
* color (r, g, b). If the image has uniform color and alpha (or alpha is zero,
* in which case the color is always uniform) then we won't bother returning
* a surface for it.
void cairo_draw_with_xlib(cairo_t* cr, cairo_xlib_drawing_callback callback,
void* closure, Display* dpy, unsigned int width,
unsigned int height,
cairo_xlib_drawing_opacity_t is_opaque,
cairo_xlib_drawing_support_t capabilities,
cairo_xlib_drawing_result_t* result);