open_canvas, clear_canvas, draw_obj

open_canvas(id[,geometry])

:: Opens a canvas, which is a window for drawing objects.

clear_canvas(id,index)

:: Clears a canvas.

draw_obj(id,index,pointorsegment [,color])

:: Draws a point or a line segment on a canvas.

return

0

id, index, color

integer

pointorsegment

list

• These functions are supplied by the OpenXM server `ox_plot' (`engine' on Windows).
• open_canvas opens a canvas, which is a window for drawing objecgts. One can specifies the size of a canvas in pixel by supplying geometry option [x,y]. The default size is [300,300]. This function pushes an integer value onto the stack of the OpenXM server. The value is used to distiguish the opened canvas and one has to pop and maintain the value by ox_pop_cmo for subsequent calls of draw_obj.
• clear_canvas clears a canvas specified by a server id id and a canvas id index.
• draw_obj_canvas draws a point or a line segment on a canvas specified by a server id id and a canvas id index. If pointorsegment is [x,y], it is regarded as a point. If pointorsegment is [x,y,u,v], it is regarded as a line segment which connects [x,y] and [u,v]. If color is specified, color/65536 mod 256, color/256 mod 256, color mod 256 are regarded as the vaules of Red, Green, Blue (Max. 255) respectively.

[182] Id=ox_launch_nox(0,"ox_plot");
0
[183] open_canvas(Id);
0
[184] Ind=ox_pop_cmo(Id);
0
[185] draw_obj(Id,Ind,[100,100]);
0
[186] draw_obj(Id,Ind,[200,200],0xffff);
0
[187] draw_obj(Id,Ind,[10,10,50,50],0xff00ff);
0
[188] clear_canvas(Id,Ind);
0

References

section ox_launch, ox_launch_nox, ox_shutdown, section ox_reset,ox_intr,register_handler, section ox_pop_cmo, ox_pop_local.

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