X-Windows

From 7b52cc13af4e85f1ca2deb6b6c77de9c95ea0dcf Mon Sep 17 00:00:00 2001 From: scuri Date: Fri, 17 Oct 2008 06:10:33 +0000 Subject: First commit - moving from LuaForge to SourceForge --- html/en/drv/xrender.html | 152 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 152 insertions(+) create mode 100644 html/en/drv/xrender.html (limited to 'html/en/drv/xrender.html') diff --git a/html/en/drv/xrender.html b/html/en/drv/xrender.html new file mode 100644 index 0000000..6970e29 --- /dev/null +++ b/html/en/drv/xrender.html @@ -0,0 +1,152 @@ + + + + + + +X-Windows + + + + + +

XRender Base Driver

+ +

This driver represents a basic driver for all system-dependent drivers + implemented in the X-Windows system using the XRender extension. The implementation uses the + XRender and Xft API functions.

The main motivation for the use of XRender was transparency for all the primitives. Beyond that we got other features + like anti-aliasing, gradient filling and transformations.

This driver still does not completely replace the X-Windows base driver, because + XRender does not have support for + XOR and for line styles.

So we let the programmer to choose what to use. We created the function + cdUseContextPlus that allows to activate or to deactivate the use of + X-Render for the available X-Windows based drivers. + This function affects only the cdCreateCanvas function call, once created + the canvas will be always a XRender canvas. In fact the function affects primary the definitions + CD_NATIVEWINDOW, + CD_IMAGE and + CD_DBUFFER, because they are + function calls and not static defines.

Using XRender it is allowed to create more that one canvas at the same time for the same Window. And they can co-exist + with a standard X-Windows canvas.

To enable the use of XRender based drivers you must call the initialization function + cdInitContextPlus() once and link to the libraries "cdcontextplus", "Xrender" and "Xft". + Also the libraries "Xrender" and "Xft" + must be installed in your system. The XRender extension must be available in + the X-Windows server for the driver to work.

Currently, pre-compiled binaries are available for Linux, Darwin +and FreeBSD54. It is not available for the systems we have with AIX, SunOS and +IRIX.

In CDLua it is not necessary any additional initialization, but the + application must still be linked with the cdcontextplus.lib + library or a require"cdluacontextplus" can be used when + using dynamic libraries.

+ +

Behavior of Functions

Control

+ Play: does nothing, returns + CD_ERROR.

Coordinate System and Clipping

+ + UpdateYAxis: the + orientation of axis Y is the opposite to its orientation in the CD library. + Except when using transformations.

Primitives

Line: + simulated using the client's Poly.
Text: + Generic transformation + matrix affects only the position of the text. Complex clipping regions can not + contain text regions.
+ Begin: + CD_BEZIER is simulated with lines.
Rect: + simulated using the client's Line.
Arc: + simulated using the client's Line.
Sector: + simulated using the client's Poly.
Chord: + simulated using the client's Poly
Box: + simulated using the client's Poly.

Attributes

+ + LineWidth: the driver will + use a polygon that fits to the line extents, even when linewidth==1.
+ + LineStyle: NOT supported.
+ Pattern: each pixel can contain transparency information.
+ + NativeFont: also accepts the + X-Windows font string format. You can use program xfontsel to select a font and obtain the string. + For ex: "-*-times-bold-r-*-*-24-*-*-*-*-*-*-*" (equivalent of Font("Times", + CD_BOLD, -24).
+ Font: font support is + implemented using the Xft library. Internally the Xft library uses the + Freetype library.

Colors

+ Use the X-Windows base driver support for colors.

Client and Server Images

+ All functions use the X-Windows base driver functions.

Exclusive Attributes

"GC": returns the X11 graphics + context (get only). In Lua is returned as a user data.

+ +

"ROTATE": allows the usage of 1 + angle and 1 coordinate (x, y), that define a global rotation transformation + centered in the specified coordinate. Use 1 real and 2 integer values inside a + string ("%g %d %d" = angle x y). In this driver will change the + current transformation matrix, if removed will reset the current + transformation matrix.

+ +

"ANTIALIAS": controls the use of anti-aliasing + for the text, image zoom and line + drawing primitives. Assumes values "1" (active) and "0" (inactive). Default value: "1".

+ +

"LINEGRADIENT": defines a filled interior style that uses a line gradient + between two colors. It uses 2 points ("%d %d %d %d" = x1 y1 x2 y2), one for the starting point using (using the + foreground color), and another one for the end point (using the background color). + (available only if Xrender version >= 0.10)

+ +

"XRENDERVERSION": returns a + string with the XRender version number. It is empty if the XRender extension + is not available in the X-Windows server.

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