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/xwin.html | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 html/en/drv/xwin.html (limited to 'html/en/drv/xwin.html') diff --git a/html/en/drv/xwin.html b/html/en/drv/xwin.html new file mode 100644 index 0000000..cd2d900 --- /dev/null +++ b/html/en/drv/xwin.html @@ -0,0 +1,129 @@ + + + + + + +X-Windows + + + + + + +

X-Windows Base Driver

+ +

This driver represents a basic driver for all system-dependent drivers + implemented in the X-Windows system. The implementation uses the XLIB API + functions. It was developed using X11R4, but works in more recent versions, + such as X11R6.

Note: The coordinates internally implemented by the video driver use 16-bit + integers. Therefore, if a coordinate with less than -32k or more than 32k is + defined, it will be interpreted incorrectly.

+ +

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.

Primitives

Text: + text orientation is simulated using XVertex rotines. Generic transformation + matrix affects only the position of the text.
+ Begin: Filled + polygons have an error of one pixel to the right and below. + CD_BEZIER is simulated with lines.
+ Box: in Linux with ATI board, is being drawn with one + extra pixel to the right and below.

Attributes

+ + LineWidth: if + width is 1, the driver will use 0 for a better + performance.
+ + LineStyle: thick lines have + style only in the line's direction. For example, you will see small rectangles + in a thick dotted line.
+ + 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: the old name "System" + is mapped to "fixed".

Colors

+ + Palette: When the number of + bits per pixel is smaller than or equal to 8, the driver will use the system + palette to solve colors passed as parameters to the canvas. The driver + allocates colors as they are requested - if a color cannot be allocated, the + closest color is used in the palette. For such, the driver sees all available + colors, in the current application and others. If one of the applications is + terminated, a color in the palette may become invalid and will only be updated + by the driver when it is requested again. For this reason, a call to + cdForeground or cdBackground or cdPalette + is recommended before drawing.
+ When CD_FORCE is used, the driver forces color allocation in the X server. + This may imply changing colors in other applications when a cursor moves in + and out of the canvas. However, if the number of requested colors is smaller + than the maximum number of possible colors in the palette, then the first + colors in the default system palette will be preserved, minimizing this + problem.
+ When CD_POLITE is used, all colors allocated by the driver are liberated, and + the requested colors are allocated. This is useful for the application to + prioritize the colors that will be allocated, causing other colors to be + mapped to their closest colors.
+ Note that canvases in the same application interfere with one another, but + when a canvas is terminated it liberates all allocated colors.

Client Images

+ + GetImageRGB: can be very + slow due to the heavy conversions performed to translate data in system format + into RGB vectors.

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.

+ + + + -- cgit v1.2.3