TCL UTILITIES

Arc	TCL UTILITIES USER MANUAL	Arc

SYNOPSIS

Draw an arc or circle in a graphics window

PACKAGE

TCLGPH

NAME

Arc

USAGE

Arc	wnID X Y Z R bA eA MkSq MkPie Res {Tag}

INPUT DEFINITIONS

wnID	-	The iD of the window to output the arc in.
X	-	The X coordinate of the center of the arc.
Y	-	The Y coordinate of the center of the arc.
Z	-	The Z coordinate of the center of the arc. Unused with the TK graphics driver but perhaps not with the VTK driver.
R	-	The radius of the arc.
bA	-	The beginning angle in degrees of the arc.
bE	-	The end angle in degrees of the arc.
MkSq	-	Flag indicating that the arc should be drawn as if its being output in a window with a 1:1 aspect ratio. Arc's drawn in rectangular windows are drawn with the aspect of the window (circles become ellipses). Set to X or Y to output as if the window has a 1:1 aspect ratio with the requested radius being measured against the X or Y axis respectively. Set to any other value to draw the circle using the aspect ratio of the window.
MkPie	-	Set to 1 if when drawing an an arc you want lines drawn from end points to the center. Set to 0 for not lines.
Res	-	The angular resolution to use when drawing the arc. Set to -1 to get maximum resolution. An N-sided polygons can be created by setting the resolution to 360/N.
Tag	-	Optional input variable which allows the arc to have the designated Tag attached to it. Tagged items can be selectively deleted from a canvas.

RETURN DEFINITION

NONE

DESCRIPTION

Arc draws an arc in the graphics window wnID of radius R, centered at (X, Y, Z). The arc begins at bA and ends at eA. To draw a circle set bA to 0 and eA to 360.
The arc is drawn with the same aspect ratio as the window it is drawn in. A circle drawn in a rectangular window will be seen as an ellipse. Setting MkSq to either X or Y will draw the arc as though the window has a 1:1 aspect ratio with the radius distance determined from the X or Y axis respectively. Note: This works only if the axes are scaled so that they also have a 1:1 ratio.
The arc is output either filled or empty depending on the last call to PlotColor. It can also be output as a pie slice by setting MkPie to 1.

ERRORS

None Generated

C BACKING

EXAMPLE(S)

EXAMPLE 1:Examples of various arcs.

# INITIALIZE the default gui settings

GUIprefsRead

# SET a window size

set GphInfo(xsScrL) 600
set GphInfo(ysScrL) 500
set GphInfo(xScrL) 600
set GphInfo(yScrL) 500

# START graphics

GraphicsOn TK RainBow SWAP

# ESTABLISH a graphics window coverting the whole canvas 

GenWindow 0 0.0 0.0 0.0 1.0 1.0 1.0 -6.0 -6.0 0.0 6.0 6.0 0.0

# DRAW three circle. The white circle is drawn using the aspect ratio 
#  of the window, the red circle uses a 1:1 aspect ratio with the radial
#  length determined from the X axis and the green circle uses a 1:1 
#  aspect ratio but the radial length determined from the Y.

PlotColor HOLD $GphInfo(White) HOLD
Arc 0 0.0 0.0 0.0 3.0 0.0 360.0 0 0 -1.
PlotColor HOLD $GphInfo(Red) HOLD
Arc 0 0.0 0.0 0.0 3.0 0.0 360.0 X 0 -1.
PlotColor HOLD $GphInfo(Green) HOLD
Arc 0 0.0 0.0 0.0 3.0 0.0 360.0 Y 0 -1.

# DRAW 12 sided polygon in blue by setting Res to 30.0

PlotColor HOLD $GphInfo(Blue) HOLD
Arc 0 0.0 0.0 0.0 2.0 0.0 360.0 Y 0 30.0

# 30 degree pie slices in the same format and colors as the circles

PlotColor HOLD $GphInfo(White) HOLD
Arc 0 2.5 2.5 0.0 2.0 30.0 60.0 0 1 -1.
PlotColor HOLD $GphInfo(Red) HOLD
Arc 0 2.5 2.5 0.0 2.0 30.0 60.0 X 1 -1.
PlotColor HOLD $GphInfo(Green) HOLD
Arc 0 2.5 2.5 0.0 2.0 30.0 60.0 Y 1 -1.

# 30 degree arcs in the same format and colors as the circles

PlotColor HOLD $GphInfo(White) HOLD
Arc 0 -2.5 2.5 0.0 2.0 120.0 150.0 0 0 -1.
PlotColor HOLD $GphInfo(Red) HOLD
Arc 0 -2.5 2.5 0.0 2.0 120.0 150.0 X 0 -1.
PlotColor HOLD $GphInfo(Green) HOLD
Arc 0 -2.5 2.5 0.0 2.0 120.0 150.0 Y 0 -1.

# 60 degree filled arcs arranged in a circle ala color wheel.  The
#   arcs are drawn with a 1:1 appect ratio.

PlotColor HOLD $GphInfo(Red) $GphInfo(Red)
Arc 0 -3.5 -3.5 0.0 1.0 0.0 60.0 Y 1 -1.
PlotColor HOLD $GphInfo(Yellow) $GphInfo(Yellow)
Arc 0 -3.5 -3.5 0.0 1.0 60.0 120.0 Y 1 -1.
PlotColor HOLD $GphInfo(Green) $GphInfo(Green)
Arc 0 -3.5 -3.5 0.0 1.0 120.0 180.0 Y 1 -1.
PlotColor HOLD $GphInfo(Cyan) $GphInfo(Cyan)
Arc 0 -3.5 -3.5 0.0 1.0 180.0 240.0 Y 1 -1.
PlotColor HOLD $GphInfo(Blue) $GphInfo(Blue)
Arc 0 -3.5 -3.5 0.0 1.0 240.0 300.0 Y 1 -1.
PlotColor HOLD $GphInfo(Purple) $GphInfo(Purple)
Arc 0 -3.5 -3.5 0.0 1.0 300.0 360.0 Y 1 -1.

# Same as above but drawn with the window aspec ratio.

PlotColor HOLD $GphInfo(Red) $GphInfo(Red)
Arc 0 3.5 -3.5 0.0 1.0 0.0 60.0 0 1 -1.
PlotColor HOLD $GphInfo(Yellow) $GphInfo(Yellow)
Arc 0 3.5 -3.5 0.0 1.0 60.0 120.0 0 1 -1.
PlotColor HOLD $GphInfo(Green) $GphInfo(Green)
Arc 0 3.5 -3.5 0.0 1.0 120.0 180.0 0 1 -1.
PlotColor HOLD $GphInfo(Cyan) $GphInfo(Cyan)
Arc 0 3.5 -3.5 0.0 1.0 180.0 240.0 0 1 -1.
PlotColor HOLD $GphInfo(Blue) $GphInfo(Blue)
Arc 0 3.5 -3.5 0.0 1.0 240.0 300.0 0 1 -1.
PlotColor HOLD $GphInfo(Purple) $GphInfo(Purple)
Arc 0 3.5 -3.5 0.0 1.0 300.0 360.0 0 1 -1.

Feb 22, 2007