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I'm working on Autocad files reader for android , now I Only read DXF files using Kabeja library and it works great but when i draw simple shape in Autocad and try to draw it on Android it doesn't appear when i look to Autocad coordinates i find them are too large I have already did a lot of search to find out any solution and one i tried is to read

EXTMIN and EXTMAX

header values but they return {30=0.0, 20=1015.620062425179, 10=1624.318980044965} for EXTMIN and {30=0.0, 20=2134.42060268589, 10=3716.108222970341} for EXTMAX

this is my code 

DXFHeader dxfHeader = dxfDoc.getDXFHeader();
DXFVariable dxfVariableMin = dxfHeader.getVariable("$EXTMIN");
DXFVariable dxfVariableMax = dxfHeader.getVariable("$EXTMAX");

i don't know how to use these values to make my shapes be drawn correctly

Maxence
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Ma7moud El-Naggar
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1 Answers1

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EXTMIN and EXTMAX define the area of the dxf drawing that contains geometry (entities).

When displaying a dxf file, you would use the EXTMIN values as an offset.

In your example, the lower-left corner of dxf file area that contains geometry is:

1624.318980044965, 1015.620062425179

while the upper-right corner is:

3716.108222970341, 2134.42060268589

This means that your effective canvas size is actually 2091 wide by 1118 tall.

If you had an entity, like a circle, whose x,y center coordinates were 2000,1500; you could then subtract the EXTMIN coords and display the circle at 375.68, 484.38

As long as you subtract the EXTMIN coords from all your entities's x and y coords (10 and 20 group codes) you will be able to display a smaller area that just includes the area that contains geometry.

Stewbob
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  • that's great now i can see my entities but i have another problem my entities shifted right and above so they don't displayed as i draw them in autocad – Ma7moud El-Naggar May 30 '14 at 19:50