This represents a frame that is rendered as a window onto another (possibly much larger) canvas. You can only see the portion of the canvas that is below the window at any given time.
This works simply by automatically defining a scissor effect to be applied to a special child node, called the canvas_node, of the PGVirtualFrame node. Every object that is parented to the canvas_node will be clipped by the scissor effect. Also, you can modify the canvas_transform through convenience methods here, which actually modifies the transform on the canvas_node.
The net effect is that the virtual canvas is arbitrarily large, and we can peek at it through the scissor region, and scroll through different parts of it by modifying the canvas_transform.
PGScrollFramefor a specialization of this class that handles the traditional scrolling canvas, with scroll bars.
PGVirtualFrame(std::string const &name = "")¶
Removes the clip frame from the item. This disables clipping.
Returns the special node that holds all of the children that appear in the virtual canvas.
TransformState const *
Returns the transform of the virtual canvas. This transform is applied to all child nodes of the canvas_node.
LVecBase4 const &
Returns true if the clip frame has been set; see
set_clip_frame(). If it has not been set, objects in the virtual frame will not be clipped.
set_canvas_transform(TransformState const *transform)¶
Changes the transform of the virtual canvas. This transform is applied to all child nodes of the canvas_node.
set_clip_frame(PN_stdfloat left, PN_stdfloat right, PN_stdfloat bottom, PN_stdfloat top)¶
set_clip_frame(LVecBase4 const &clip_frame)¶
Sets the bounding rectangle of the clip frame. This is the size of the small window through which we can see the virtual canvas. Normally, this is the same size as the actual frame or smaller (typically it is smaller by the size of the bevel, or to make room for scroll bars).