Documentation: C API comments in include/

include/c/sk_canvas.h

Index: include/c/sk_canvas.h
diff --git a/include/c/sk_canvas.h b/include/c/sk_canvas.h
index f65d3aa5c9829dd76b61b29a168ee8758ca8b713..f6c0d4e1c143f34cf1906dd46c1ce761931c1368 100644
--- a/include/c/sk_canvas.h
+++ b/include/c/sk_canvas.h
@@ -15,29 +15,137 @@
 
 SK_C_PLUS_PLUS_BEGIN_GUARD
 
+/**
+    Save the current matrix and clip on the canvas.  When the
+    balancing call to sk_canvas_restore() is made, the previous matrix
+    and clip are restored.
+*/
 SK_API void sk_canvas_save(sk_canvas_t*);
+/**
+    This behaves the same as sk_canvas_save(), but in addition it
+    allocates an offscreen surface. All drawing calls are directed
+    there, and only when the balancing call to sk_canvas_restore() is
+    made is that offscreen transfered to the canvas (or the previous
+    layer).
+
+    @param sk_rect_t* (may be null) This rect, if non-null, is used as
+                      a hint to limit the size of the offscreen, and
+                      thus drawing may be clipped to it, though that
+                      clipping is not guaranteed to happen. If exact
+                      clipping is desired, use sk_canvas_clip_rect().
+    @param sk_paint_t* (may be null) The paint is copied, and is applied
+                       to the offscreen when sk_canvas_restore() is
+                       called.
+*/
 SK_API void sk_canvas_save_layer(sk_canvas_t*, const sk_rect_t*, const sk_paint_t*);
+/**
+    This call balances a previous call to sk_canvas_save() or
+    sk_canvas_save_layer(), and is used to remove all modifications to
+    the matrix and clip state since the last save call.  It is an
+    error to call sk_canvas_restore() more times than save and
+    save_layer were called.
+*/
 SK_API void sk_canvas_restore(sk_canvas_t*);
 
+/**
+    Preconcat the current coordinate transformation matrix with the
+    specified translation.
+*/
 SK_API void sk_canvas_translate(sk_canvas_t*, float dx, float dy);
+/**
+    Preconcat the current coordinate transformation matrix with the
+    specified scale.
+*/
 SK_API void sk_canvas_scale(sk_canvas_t*, float sx, float sy);
+/**
+    Preconcat the current coordinate transformation matrix with the
+    specified rotation in degrees.
+*/
 SK_API void sk_canvas_rotate_degrees(sk_canvas_t*, float degrees);
+/**
+    Preconcat the current coordinate transformation matrix with the
+    specified rotation in radians.
+*/
 SK_API void sk_canvas_rotate_radians(sk_canvas_t*, float radians);
+/**
+    Preconcat the current coordinate transformation matrix with the
+    specified skew.
+*/
 SK_API void sk_canvas_skew(sk_canvas_t*, float sx, float sy);
+/**
+    Preconcat the current coordinate transformation matrix with the
+    specified matrix.
+*/
 SK_API void sk_canvas_concat(sk_canvas_t*, const sk_matrix_t*);
 
+/**
+    Modify the current clip with the specified rectangle.  The new
+    current clip will be the intersection of the old clip and the
+    rectange.
+*/
 SK_API void sk_canvas_clip_rect(sk_canvas_t*, const sk_rect_t*);
+/**
+    Modify the current clip with the specified path.  The new
+    current clip will be the intersection of the old clip and the
+    path.
+*/
 SK_API void sk_canvas_clip_path(sk_canvas_t*, const sk_path_t*);
 
+/**
+    Fill the entire canvas (restricted to the current clip) with the
+    specified paint.
+*/
 SK_API void sk_canvas_draw_paint(sk_canvas_t*, const sk_paint_t*);
+/**
+    Draw the specified rectangle using the specified paint. The
+    rectangle will be filled or stroked based on the style in the
+    paint.
+*/
 SK_API void sk_canvas_draw_rect(sk_canvas_t*, const sk_rect_t*, const sk_paint_t*);
+/**
+    Draw the specified oval using the specified paint. The oval will be
+    filled or framed based on the style in the paint
+*/
 SK_API void sk_canvas_draw_oval(sk_canvas_t*, const sk_rect_t*, const sk_paint_t*);
+/**
+    Draw the specified path using the specified paint. The path will be
+    filled or framed based on the style in the paint
+*/
 SK_API void sk_canvas_draw_path(sk_canvas_t*, const sk_path_t*, const sk_paint_t*);
+/**
+    Draw the specified image, with its top/left corner at (x,y), using
+    the specified paint, transformed by the current matrix.
+
+    @param sk_paint_t* (may be NULL) the paint used to draw the image.
+*/
 SK_API void sk_canvas_draw_image(sk_canvas_t*, const sk_image_t*,
                                  float x, float y, const sk_paint_t*);
+/**
+    Draw the specified image, scaling and translating so that it fills
+    the specified dst rect. If the src rect is non-null, only that
+    subset of the image is transformed and drawn.
+
+    @param sk_paint_t* (may be NULL) The paint used to draw the image.
+*/
 SK_API void sk_canvas_draw_image_rect(sk_canvas_t*, const sk_image_t*,
                                       const sk_rect_t* src,
                                       const sk_rect_t* dst, const sk_paint_t*);
+
+/**
+    Draw the picture into this canvas (replay the pciture's drawing commands).
+
+    @param sk_matrix_t* If non-null, apply that matrix to the CTM when
+                        drawing this picture. This is logically
+                        equivalent to: save, concat, draw_picture,
+                        restore.
+
+    @param sk_paint_t* If non-null, draw the picture into a temporary
+                       buffer, and then apply the paint's alpha,
+                       colorfilter, imagefilter, and xfermode to that
+                       buffer as it is drawn to the canvas.  This is
+                       logically equivalent to save_layer(paint),
+                       draw_picture, restore.
+*/
 SK_API void sk_canvas_draw_picture(sk_canvas_t*, const sk_picture_t*,
                                    const sk_matrix_t*, const sk_paint_t*);