PtGraphic
PtGraphic — A parent class for graphic widget resources.
Synopsis
class PtGraphic PtBasic
{
dash_list; // char array (Pt_ARG_DASH_LIST)
dash_scale; // long (Pt_ARG_DASH_SCALE)
graphic_flags; // flag (Pt_ARG_GRAPHIC_FLAGS)
line_cap; // unsigned short (Pt_ARG_LINE_CAP)
line_join; // unsigned short (Pt_ARG_LINE_JOIN)
line_width; // long (Pt_ARG_LINE_WIDTH)
origin; // PhPoint (Pt_ARG_ORIGIN)
points; // PhPoint array (Pt_ARG_POINTS)
}
Description
This widget serves as a
parent class of resources for graphic widgets, and is not
normally instantiated. The variables here have to do mainly
with line origins, thicknesses, joints and caps, as well as
fill colors for closed shapes.
![[Note]](images/note.gif) | For detailed information, please refer to PtGraphic
in the Photon documentation.
|
Instance Variables
- dash_list
An array of integers specifying in pixels the length of
each dash and/or space for dashed lines. If there is more
than one element in the array, each element applies to the
next dash or space, and then the pattern repeats. An array
with an odd number of elements will produce an alternating
pattern of dashes and spaces (see the example below). The
default is an empty array [ ], which gives
a solid line.
| Setting this variable to an array of length
0 with a Gamma statement like this:
GraphicInstance.dash_list = array(0);
will cause undefined behavior. To reset the default, use
array(). |
- dash_scale
A 32 bit number that specifies the scale of
the dash_list. The top 16 bits
correspond to numbers greater than one, the bottom
16 to fractions less than one. The number
0x00010000 is equal to one.
For example, to scale
dashes 2 times larger, you would use the number
0x00020000; to make them half size, you would use
0x00008000 (because that is half of
0x00010000). See also the example below.
- graphic_flags
This instance variable controls
the position and origin of the widget and the graphic
with respect to the parent widget. It may be a
combination of zero (the default) or more of the
following flags:
- line_cap
A constant that determines the shape of line
ends, which become visible when a line is fairly wide.
The default is butted, which means the line ends
squarely at the end point. You can put a round or
square cap at the end, which overlaps the end point by
a factor of half the line width.
This
instance variable may have one of the following
values:
- line_join
This instance variable determines
the shape of line joints (mainly visible for wide lines),
and may have one of the following values:
- line_width
- A number specifying the width of a line, in pixels.
- origin
- A PhPoint specifying
the origin of the widget, which is the upper-left
corner of its widget canvas.
- points
- An array of PhPoints
defining the graphic. The number and purpose of
the points depends on the type of graphic.
Example
This example,
ex_PtGraphics.g, is included in the product distribution.
#!/usr/cogent/bin/phgamma
/*
* This example illustrates dash variables for graphic lines.
*/
require_lisp("PhotonWidgets.lsp");
require_lisp("PhabTemplate.lsp");
PtInit(nil);
wfile = PhabReadWidgetFile (string(_os_, "-WidgetFiles/wgt/graphics.wgtw"));
window = PhabCreateWidgets(wfile, nil, nil);
win = PhabLookupWidget(window,#graphics,nil);
ln0 = PhabLookupWidget(window,#Line0,nil);
ln1 = PhabLookupWidget(window,#Line1,nil);
ln2 = PhabLookupWidget(window,#Line2,nil);
ln3 = PhabLookupWidget(window,#Line3,nil);
ln4 = PhabLookupWidget(window,#Line4,nil);
ln5 = PhabLookupWidget(window,#Line5,nil);
ebut = PhabLookupWidget(window,#ExitButton,nil);
PtAttachCallback(ebut, Pt_CB_ACTIVATE, #exit_program(1));
ln0.dash_list = array();
ln1.dash_list = array(20);
ln2.dash_list = array(20,5);
ln3.dash_list = array(20,5,20);
ln4.dash_list = array(20);
ln4.dash_scale = 0x00020000;
ln5.dash_list = array(20);
ln5.dash_scale = 0x00004000;
PtRealizeWidget(win);
PtMainLoop();
Callbacks
The following callback is associated with this widget:
