gfx/thebes/src/cairo-xlib-utils.h

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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   6  * 1.1 (the "License"); you may not use this file except in compliance with
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  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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  14  *
  15  * The Original Code is Novell code.
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  17  * The Initial Developer of the Original Code is Novell.
  18  * Portions created by the Initial Developer are Copyright (C) 2006
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  21  * Contributor(s):
  22  *   rocallahan@novell.com
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  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #ifndef CAIROXLIBUTILS_H_
  39 #define CAIROXLIBUTILS_H_
  40
  41 #include "cairo.h"
  42 #include <X11/Xlib.h>
  43
  44 CAIRO_BEGIN_DECLS
  45
  46 /**
  47  * This callback encapsulates Xlib-based rendering. We assume that the
  48  * execution of the callback is equivalent to compositing some RGBA image of
  49  * size (bounds_width, bounds_height) onto the drawable at offset (offset_x,
  50  * offset_y), clipped to the union of the clip_rects if num_rects is greater
  51  * than zero. This includes the assumption that the same RGBA image
  52  * is composited if you call the callback multiple times with the same closure,
  53  * display and visual during a single cairo_draw_with_xlib call.
  54  *
  55  * @return True on success, False on non-recoverable error
  56  */
  57 typedef cairo_bool_t (* cairo_xlib_drawing_callback)
  58     (void *closure,
  59      Display *dpy,
  60      Drawable drawable,
  61      Visual *visual,
  62      short offset_x, short offset_y,
  63      XRectangle* clip_rects, unsigned int num_rects);
  64
  65 /**
  66  * This structure captures the result of the native drawing, in case the
  67  * caller may wish to reapply the drawing efficiently later.
  68  */
  69 typedef struct {
  70     cairo_surface_t *surface;
  71     cairo_bool_t    uniform_alpha;
  72     cairo_bool_t    uniform_color;
  73     double          alpha; /* valid only if uniform_alpha is TRUE */
  74     double          r, g, b; /* valid only if uniform_color is TRUE */
  75 } cairo_xlib_drawing_result_t;
  76
  77 /**
  78  * This type specifies whether the native drawing callback draws all pixels
  79  * in its bounds opaquely, independent of the contents of the target drawable,
  80  * or whether it leaves pixels transparent/translucent or depends on the
  81  * existing contents of the target drawable in some way.
  82  */
  83 typedef enum _cairo_xlib_drawing_opacity {
  84     CAIRO_XLIB_DRAWING_OPAQUE,
  85     CAIRO_XLIB_DRAWING_TRANSPARENT
  86 } cairo_xlib_drawing_opacity_t;
  87
  88 /**
  89  * This type encodes the capabilities of the native drawing callback.
  90  *
  91  * If CAIRO_XLIB_DRAWING_SUPPORTS_OFFSET is set, 'offset_x' and 'offset_y'
  92  * can be nonzero in the call to the callback; otherwise they will be zero.
  93  *
  94  * If CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_RECT is set, then 'num_rects' can be
  95  * zero or one in the call to the callback. If
  96  * CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_LIST is set, then 'num_rects' can be
  97  * anything in the call to the callback. Otherwise 'num_rects' will be zero.
  98  * Do not set both of these values.
  99  *
 100  * If CAIRO_XLIB_DRAWING_SUPPORTS_ALTERNATE_DISPLAY is set, then 'dpy' can be
 101  * any display, otherwise it will be the display passed into
 102  * cairo_draw_with_xlib.
 103  *
 104  * If CAIRO_XLIB_DRAWING_SUPPORTS_NONDEFAULT_VISUAL is set, then 'visual' can be
 105  * any visual, otherwise it will be equal to
 106  * DefaultVisual (dpy, DefaultScreen (dpy)).
 107  */
 108 typedef enum {
 109     CAIRO_XLIB_DRAWING_SUPPORTS_OFFSET = 0x01,
 110     CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_RECT = 0x02,
 111     CAIRO_XLIB_DRAWING_SUPPORTS_CLIP_LIST = 0x04,
 112     CAIRO_XLIB_DRAWING_SUPPORTS_ALTERNATE_DISPLAY = 0x08,
 113     CAIRO_XLIB_DRAWING_SUPPORTS_NONDEFAULT_VISUAL = 0x10
 114 } cairo_xlib_drawing_support_t;
 115
 116 /**
 117  * Draw Xlib output into any cairo context. All cairo transforms and effects
 118  * are honored, including the current operator. This is equivalent to a
 119  * cairo_set_source_surface and then cairo_paint.
 120  * @param cr the context to draw into
 121  * @param callback the code to perform Xlib rendering
 122  * @param closure associated data
 123  * @param dpy an X display to use in case the cairo context has no associated X display
 124  * @param width the width of the putative image drawn by the callback
 125  * @param height the height of the putative image drawn by the callback
 126  * @param is_opaque set to CAIRO_XLIB_DRAWING_IS_OPAQUE to indicate
 127  * that all alpha values of the putative image will be 1.0; the pixels drawn into
 128  * the Drawable must not depend on the prior contents of the Drawable
 129  * in any way
 130  * @param capabilities the capabilities of the callback as described above.
 131  * @param result if non-NULL, we *may* fill in the struct with information about
 132  * the rendered image. 'surface' may be filled in with a surface representing
 133  * the image, similar to the target of 'cr'. If 'uniform_alpha' is True then
 134  * every pixel of the image has the same alpha value 'alpha'. If
 135  * 'uniform_color' is True then every pixel of the image has the same RGB
 136  * color (r, g, b). If the image has uniform color and alpha (or alpha is zero,
 137  * in which case the color is always uniform) then we won't bother returning
 138  * a surface for it.
 139  */
 140 void cairo_draw_with_xlib (cairo_t *cr,
 141                            cairo_xlib_drawing_callback callback,
 142                            void *closure,
 143                            Display *dpy,
 144                            unsigned int width, unsigned int height,
 145                            cairo_xlib_drawing_opacity_t is_opaque,
 146                            cairo_xlib_drawing_support_t capabilities,
 147                            cairo_xlib_drawing_result_t *result);
 148
 149 CAIRO_END_DECLS
 150
 151 #endif /*CAIROXLIBUTILS_H_*/