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Diffstat (limited to '')
| -rw-r--r-- | gfx/thebes/cairo-xlib-utils.h | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/gfx/thebes/cairo-xlib-utils.h b/gfx/thebes/cairo-xlib-utils.h new file mode 100644 index 0000000000..0125ff12cb --- /dev/null +++ b/gfx/thebes/cairo-xlib-utils.h @@ -0,0 +1,115 @@ +/* -*- 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 http://mozilla.org/MPL/2.0/. */ + +#ifndef CAIROXLIBUTILS_H_ +#define CAIROXLIBUTILS_H_ + +#include "cairo.h" +#include <X11/Xlib.h> + +CAIRO_BEGIN_DECLS + +/** + * 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_OPAQUE, + CAIRO_XLIB_DRAWING_TRANSPARENT +} 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. + * + * If CAIRO_XLIB_DRAWING_SUPPORTS_ALTERNATE_SCREEN is set, then 'screen' can + * be any screen on any display, otherwise it will be the default screen of + * the display passed into cairo_draw_with_xlib. + * + * If CAIRO_XLIB_DRAWING_SUPPORTS_NONDEFAULT_VISUAL is set, then 'visual' can be + * any visual, otherwise it will be equal to + * DefaultVisualOfScreen (screen). + */ +typedef enum { + CAIRO_XLIB_DRAWING_SUPPORTS_OFFSET = 0x01, + CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_RECT = 0x02, + CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_LIST = 0x04, + CAIRO_XLIB_DRAWING_SUPPORTS_ALTERNATE_SCREEN = 0x08, + CAIRO_XLIB_DRAWING_SUPPORTS_NONDEFAULT_VISUAL = 0x10 +} 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); + +CAIRO_END_DECLS + +#endif /*CAIROXLIBUTILS_H_*/ |