Add wrapper for cairo_recording_surface_ink_extents()

samples/Samples.md

@@ -188,6 +188,11 @@ Example of using Recording surface, simple copy, then scaled and offset.
 ![sample record0.png](sample_record0.png "record0 example")
 ![sample record1.png](sample_record1.png "record1 example")
 
+Example of using Recording surface, find the `ink_extents` of drawing operations, 
+draw an encompassing rectangle, scale and offset.
+
+![sample record inkextents.png](sample_record_inkextents.png "record inkextents example")
+
 Example of writing to script, put script text into frame.
 
 ![sample script0.png](sample_script0.png "scrip0 example")

samples/sample_record_inkextents.jl

@@ -0,0 +1,53 @@
+## header to provide surface and context
+using Cairo
+c = CairoARGBSurface(256,256);
+cr = CairoContext(c);
+
+save(cr);
+set_source_rgba(cr,0.0,0.0,0.0,0.0); # transparent black
+rectangle(cr,0.0,0.0,256.0,256.0); # background
+fill(cr);
+restore(cr);
+save(cr);
+
+## paint the following to a Recording Surface
+s1 = CairoRecordingSurface()
+c1 = CairoContext(s1)
+
+move_to(c1, 128.0, 25.6);
+line_to(c1, 230.4, 230.4);
+rel_line_to(c1, -102.4, 0.0);
+curve_to(c1, 51.2, 230.4, 51.2, 128.0, 128.0, 128.0);
+close_path(c1);
+
+move_to(c1, 64.0, 25.6);
+rel_line_to(c1, 51.2, 51.2);
+rel_line_to(c1, -51.2, 51.2);
+rel_line_to(c1, -51.2, -51.2);
+close_path(c1);
+
+set_line_width(c1, 10.0);
+set_source_rgb(c1, 0, 0, 1);
+fill_preserve(c1);
+set_source_rgb(c1, 0, 0, 0);
+stroke(c1);
+
+## find ink extents and mark with a rectangle
+x0, y0, width, height = recording_surface_ink_extents(s1);
+rectangle(c1, x0, y0, width, height)
+stroke(c1);
+
+## play back on transform coord
+scale(cr,0.5,0.5)
+set_source(cr, s1, 128.0, 128.0)
+
+paint(cr)
+
+
+## mark picture with current date
+restore(cr);
+move_to(cr,0.0,12.0);
+set_source_rgb(cr, 0,0,0);
+show_text(cr,Libc.strftime(time()));
+write_to_png(c,"sample_record_inkextents.png");
+

src/Cairo.jl

@@ -72,7 +72,7 @@ export
     set_source_rgb, set_source_rgba, set_source_surface, set_line_type,
     set_line_cap, set_line_join,
     set_operator, get_operator, set_source,
-    CairoMatrix,
+    CairoMatrix, recording_surface_ink_extents,
 
     # coordinate systems
     reset_transform, rotate, scale, translate, user_to_device!,
@@ -563,6 +563,16 @@ function script_from_recording_surface(s::CairoScript,r::CairoSurface)
     ccall((:cairo_script_from_recording_surface,libcairo), Int32,
                 (Ptr{Nothing},Ptr{Nothing}),s.ptr, r.ptr)
 end
+function recording_surface_ink_extents(r::CairoSurface)
+    x0 = Ref{Cdouble}(0)
+    y0 = Ref{Cdouble}(0)
+    width = Ref{Cdouble}(0)
+    height = Ref{Cdouble}(0)
+    ccall((:cairo_recording_surface_ink_extents,libcairo), Nothing,
+          (Ptr{Nothing}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), 
+          r.ptr, x0, y0, width, height)
+    x0[], y0[], width[], height[]
+end
 # -----------------------------------------------------------------------------
 
 mutable struct CairoContext <: GraphicsContext