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a7557dc8f9
Thu Apr 25 22:37:58 2002 Owen Taylor <otaylor@redhat.com>
* gdk/tmpl/{events,input_devices,region,x_interaction}.sgml:
Fix some docs duplicated between templates and inline.
310 lines
7.1 KiB
Plaintext
310 lines
7.1 KiB
Plaintext
<!-- ##### SECTION Title ##### -->
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Points, Rectangles and Regions
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<!-- ##### SECTION Short_Description ##### -->
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simple graphical data types.
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<!-- ##### SECTION Long_Description ##### -->
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<para>
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GDK provides the #GdkPoint, #GdkRectangle, #GdkRegion and #GdkSpan data types
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for representing pixels and sets of pixels on the screen.
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</para>
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<para>
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#GdkPoint is a simple structure containing an x and y coordinate of a point.
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</para>
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<para>
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#GdkRectangle is a structure holding the position and size of a rectangle.
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The intersection of two rectangles can be computed with
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gdk_rectangle_intersect(). To find the union of two rectangles use
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gdk_rectangle_union().
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</para>
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<para>
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#GdkRegion is an opaque data type holding a set of arbitrary pixels, and is
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usually used for clipping graphical operations (see gdk_gc_set_clip_region()).
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</para>
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<para>
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#GdkSpan is a structure holding a spanline. A spanline is a horizontal line that
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is one pixel wide. It is mainly used when rasterizing other graphics primitives.
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It can be intersected to regions by using gdk_region_spans_intersect_foreach().
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</para>
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<!-- ##### SECTION See_Also ##### -->
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<para>
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</para>
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<!-- ##### STRUCT GdkPoint ##### -->
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<para>
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Defines the x and y coordinates of a point.
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</para>
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@x: the x coordinate of the point.
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@y: the y coordinate of the point.
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<!-- ##### STRUCT GdkRectangle ##### -->
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<para>
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Defines the position and size of a rectangle.
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</para>
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@x: the x coordinate of the left edge of the rectangle.
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@y: the y coordinate of the top of the rectangle.
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@width: the width of the rectangle.
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@height: the height of the rectangle.
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<!-- ##### FUNCTION gdk_rectangle_intersect ##### -->
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<para>
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Calculates the intersection of two rectangles.
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</para>
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@src1: a #GdkRectangle.
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@src2: a #GdkRectangle.
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@dest: the intersection of @src1 and @src2.
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@Returns: %TRUE if the rectangles intersect.
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<!-- ##### FUNCTION gdk_rectangle_union ##### -->
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<para>
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Calculates the union of two rectangles.
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The union of rectangles @src1 and @src2 is the smallest rectangle which
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includes both @src1 and @src2 within it.
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</para>
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@src1: a #GdkRectangle.
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@src2: a #GdkRectangle.
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@dest: the union of @src1 and @src2.
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<!-- ##### STRUCT GdkRegion ##### -->
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<para>
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A GdkRegion represents a set of pixels on the screen.
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The only user-visible field of the structure is the user_data member, which
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can be used to attach arbitrary data to the #GdkRegion.
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</para>
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<!-- ##### FUNCTION gdk_region_new ##### -->
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<para>
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Creates a new empty #GdkRegion.
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</para>
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@Returns: a new empty #GdkRegion.
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<!-- ##### FUNCTION gdk_region_polygon ##### -->
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<para>
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Creates a new #GdkRegion using the polygon defined by a number of points.
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</para>
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@points: an array of #GdkPoint structs.
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@npoints: the number of elements in the @points array.
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@fill_rule: specifies which pixels are included in the region when the polygon
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overlaps itself.
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@Returns: a new #GdkRegion based on the given polygon.
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<!-- ##### ENUM GdkFillRule ##### -->
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<para>
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The method for determining which pixels are included in a region, when
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creating a #GdkRegion from a polygon.
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The fill rule is only relevant for polygons which overlap themselves.
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</para>
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@GDK_EVEN_ODD_RULE: areas which are overlapped an odd number of times are
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included in the region, while areas overlapped an even number of times are not.
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@GDK_WINDING_RULE: overlapping areas are always included.
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<!-- ##### FUNCTION gdk_region_copy ##### -->
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<para>
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</para>
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@region:
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@Returns:
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<!-- ##### FUNCTION gdk_region_rectangle ##### -->
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<para>
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</para>
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@rectangle:
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@Returns:
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<!-- ##### FUNCTION gdk_region_destroy ##### -->
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<para>
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Destroys a #GdkRegion.
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</para>
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@region: a #GdkRegion.
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<!-- ##### FUNCTION gdk_region_get_clipbox ##### -->
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<para>
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Returns the smallest rectangle which includes the entire #GdkRegion.
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</para>
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@region: a #GdkRegion.
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@rectangle: returns the smallest rectangle which includes all of @region.
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<!-- ##### FUNCTION gdk_region_get_rectangles ##### -->
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<para>
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</para>
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@region:
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@rectangles:
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@n_rectangles:
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<!-- ##### FUNCTION gdk_region_empty ##### -->
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<para>
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Returns %TRUE if the #GdkRegion is empty.
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</para>
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@region: a #GdkRegion.
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@Returns: %TRUE if @region is empty.
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<!-- ##### FUNCTION gdk_region_equal ##### -->
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<para>
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Returns %TRUE if the two regions are the same.
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</para>
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@region1: a #GdkRegion.
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@region2: a #GdkRegion.
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@Returns: %TRUE if @region1 and @region2 are equal.
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<!-- ##### FUNCTION gdk_region_point_in ##### -->
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<para>
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Returns %TRUE if a point is in a region.
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</para>
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@region: a #GdkRegion.
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@x: the x coordinate of a point.
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@y: the y coordinate of a point.
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@Returns: %TRUE if the point is in @region.
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<!-- ##### FUNCTION gdk_region_rect_in ##### -->
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<para>
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Tests whether a rectangle is within a region.
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</para>
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@region: a #GdkRegion.
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@rect: a #GdkRectangle.
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@Returns: %GDK_OVERLAP_RECTANGLE_IN, %GDK_OVERLAP_RECTANGLE_OUT, or
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%GDK_OVERLAP_RECTANGLE_PART, depending on whether the rectangle is inside,
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outside, or partly inside the #GdkRegion, respectively.
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<!-- ##### ENUM GdkOverlapType ##### -->
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<para>
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Specifies the possible values returned by gdk_region_rect_in().
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</para>
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@GDK_OVERLAP_RECTANGLE_IN: if the rectangle is inside the #GdkRegion.
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@GDK_OVERLAP_RECTANGLE_OUT: if the rectangle is outside the #GdkRegion.
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@GDK_OVERLAP_RECTANGLE_PART: if the rectangle is partly inside the #GdkRegion.
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<!-- ##### FUNCTION gdk_region_offset ##### -->
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<para>
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Moves a region the specified distance.
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</para>
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@region: a #GdkRegion.
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@dx: the distance to move the region horizontally.
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@dy: the distance to move the region vertically.
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<!-- ##### FUNCTION gdk_region_shrink ##### -->
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<para>
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Resizes a region by the specified amount.
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Positive values shrink the region. Negative values expand it.
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</para>
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@region: a #GdkRegion.
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@dx: the number of pixels to shrink the region horizontally.
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@dy: the number of pixels to shrink the region vertically.
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<!-- ##### FUNCTION gdk_region_union_with_rect ##### -->
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<para>
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</para>
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@region:
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@rect:
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<!-- ##### FUNCTION gdk_region_intersect ##### -->
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<para>
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</para>
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@source1:
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@source2:
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<!-- ##### FUNCTION gdk_region_union ##### -->
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<para>
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</para>
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@source1:
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@source2:
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<!-- ##### FUNCTION gdk_region_subtract ##### -->
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<para>
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</para>
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@source1:
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@source2:
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<!-- ##### FUNCTION gdk_region_xor ##### -->
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<para>
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</para>
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@source1:
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@source2:
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<!-- ##### STRUCT GdkSpan ##### -->
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<para>
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A GdkSpan represents a horizontal line of pixels starting
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at the pixel with coordinates @x, @y and ending before @x + @width, @y.
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</para>
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@x: x coordinate of the first pixel.
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@y: y coordinate of the first pixel.
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@width: number of pixels in the span.
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<!-- ##### USER_FUNCTION GdkSpanFunc ##### -->
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<para>
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This defines the type of the function passed to
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gdk_region_spans_intersect_foreach().
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</para>
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@span: a #GdkSpan.
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@data: the user data passed to gdk_region_spans_intersect_foreach().
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<!-- ##### FUNCTION gdk_region_spans_intersect_foreach ##### -->
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<para>
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Calls a function on each span in the intersection of @region and
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@spans.
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</para>
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@region: a #GdkRegion.
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@spans: an array of #GdkSpans.
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@n_spans: the length of @spans.
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@sorted: %TRUE if @spans is sorted wrt. the y coordinate.
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@function: function to call on each span in the intersection.
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@data: data to pass to @function.
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