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GELLIPSE()
Draw an ellipse or circle
------------------------------------------------------------------------------
Syntax
GELLIPSE(<nXc>,<nYc>,<nRadiusX>,<nRadiusY>,[<nDegStart>]
[<nDegEnd>], [<nStyle>], [<nColor>], [<nMode>],
[<nOutLineColor>], [<nHeight3D>]) --> NIL
Arguments
<nXc>, <nYc>, <nRadiusX>, and <nRadiusY> define the
ellipse center point coordinates in pixels.
Note: If <nRadiusX> and <nRadiusY> have the same value, the result
will be a circle.
<nDegStart> is the value of the starting angle in degrees. The
default value is 0.
<nDegEnd> is the value of the final angle in degrees. The default
value is 360.
Note: Changing the values of <nDegStart> and <nDegEnd> allows you
to draw arcs of a circle or ellipse and sections of a "pie chart."
<nStyle> defines the style of the ellipse using one of the constants
listed in the table below:
Ellipse Style Constants
------------------------------------------------------------------------
Constant Description
------------------------------------------------------------------------
LLG_FILL The ellipse is displayed first and then filled with the
color and mode specified below
LLG_FRAME Display of the ellipse is restricted to its contour in the
color and mode specified below
------------------------------------------------------------------------
<nColor> is a numeric value representing the display color. If this
parameter is missing, the last color specified in a call to a CA-Clipper
function is used. The value range is limited to the number of colors
available in the selected video mode. In 16-color modes, valid values
are between 0 and 15. In 256-color modes, valid values are between 0
and 255.
<nMode> is a numeric value that represents the display mode. The
following are valid <nMode> values:
Display Mode Constants
------------------------------------------------------------------------
Constant Description
------------------------------------------------------------------------
LLG_MODE_SET Display in SET mode (ignores any pixels present under the
line displayed). This is the most common display mode.
LLG_MODE_AND Display in AND mode (executes an AND on pixels present
under the line at display time and on the display color).
LLG_MODE_OR Display in OR mode (executes an OR on pixels present
under the line at display time and on the display color).
LLG_MODE_XOR Display in XOR mode (executes an XOR on pixels present
under the line at display time and on the display color).
See note.
------------------------------------------------------------------------
Note: This method allows you to move objects around on the screen
without damaging the background. To retrieve the initial background,
just repeat the call for display in XOR mode. If the display mode
parameter is missing, the last mode specified in a call to a CA-Clipper
function is used.
<nOutLineColor> is a numeric value representing the outline color.
If this parameter is missing, the last color specified in a call to a
CA-Clipper function is used. The value range is limited to the number
of colors available in the selected video mode. In 16-color modes,
valid values are between 0 and 15. In 256-color modes, valid values are
between 0 and 255.
<nHeight3D> is a numeric value representing the height of the 3-D
effect in pixels.
Returns
GELLIPSE() always returns NIL.
Description
GELLIPSE() draws an ellipse or circle. This function can be used only
if you have set the screen to a graphic mode using SET VIDEOMODE. This
function respects the constraints defined by GSETCLIP().
Examples
. This example displays an ellipse in a region limited by
clipping:
// Switch to graphic mode
SET VIDEOMODE TO LLG_VIDEO_VGA_640_480_16
// Restrict the display region to one portion of the screen
GSETCLIP(100,100,300,300)
// Draw a quarter section of an ellipse
GELLIPSE(200, 200, 160, 230, 045,;
135, LLG_FILL, 12, LLG_MODE_SET)
QUIT // End of application
Files Library is LLIBG.LLB, header file is Llibg.ch.
See Also:
GLINE()
GPOLYGON()
GRECT()
GWRITEAT()
GBMPDISP()
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