The main features of graphics ports are:
Graphics ports has two drawing modes:
:compatible |
Compatible with LispWorks 6.0 and earlier versions. |
:quality |
Introduced in LispWorks 6.1, allowing high quality drawing. |
The main visible effect is that with drawing-mode :quality
, all drawings are transformed properly.
With drawing-mode :compatible
, strings and images are not scaled or rotated at all, and ellipses are not rotated correctly. Other shapes are transformed "at the front", that is they are drawn as if the drawing function was called with transformed coordinates. The target of copy-pixels is also transformed "at the front", that is the rectangle can be translated, but not scaled or rotated.
With drawing-mode :quality
, all drawings are fully transformed correctly. Shapes are transformed "at the back", that is they are drawn and then the result of the drawing is transformed. Note that clear-rectangle and pixblt are not drawing functions in this sense, and do not take transforms into account.
Another difference is that drawing-mode :quality
supports anti-aliasing on Windows, and on GTK+ it adds control over anti-aliasing. See shape-mode and text-mode on the page for graphics-state.
With drawing-mode :quality
the operation value in the graphics-state is not supported and is ignored. This is because operations do not combine sensibly with anti-aliasing and colors with alpha components. Instead, there is now compositing-mode. For more information see the page for graphics-state.
On Microsoft Windows with drawing-mode :quality
only Truetype fonts are supported.
The drawing-mode of all graphics ports is :quality
by default, except when a graphics port is made in association with another graphics ports (for example, by create-pixmap-port), in which case the drawing-mode is inherited from the "parent" graphics port.
All the interfaces that create graphics ports, or modify a graphics port to draw to another place, take keyword argument :drawing-mode
. Its value drawing--mode can be :quality
, :compatible
, or nil
which is interpreted as use the default (either inherited or the global default :quality
). These interfaces are listed in 13.1.1 Creating instances.
These examples demonstrate features that are available only with drawing-mode :quality
:
Rotating a string:
(example-edit-file "capi/graphics/catherine-wheel")
Using compositing-mode.
(example-edit-file "capi/graphics/compositing-mode-simple")
Using compositing-mode.
(example-edit-file "capi/graphics/compositing-mode")
Using compositing-mode, transforming an image.
(example-edit-file "capi/graphics/images-with-alpha")
CAPI User Guide and Reference Manual (Windows version) - 01 Dec 2021 19:33:53