how to copy small parts of a GRAPHIC WINDOW?

[Chris Holbrook]

As in:

#COMPILE EXE
#DIM ALL

FUNCTION PBMAIN () AS LONG
    LOCAL hwina, hwTempBMP AS DWORD
    LOCAL skey AS STRING
    
    ' create a GW and fill it with a hatch pattern
    GRAPHIC WINDOW "", 200, 200, 400, 400 TO hwina
    GRAPHIC ATTACH hwina, 0
    GRAPHIC BOX (0,0) - (400,400), 0, -1, 0, 4
    skey = ""


    ' create a temporary GW just big enough to hold the area to be copied
    ' but invisible
    GRAPHIC BITMAP NEW 50, 50 TO hwTempBMP
    GRAPHIC ATTACH hwTempBMP, 0
    ' copy the area to the smaller GW
    GRAPHIC COPY hwina, 0, (0,0) - (50, 50) TO (0, 0)
    ' reconnect to the big GW
    GRAPHIC ATTACH hwina, 0
    ' reverse the hatching so the copied area will show up
    GRAPHIC BOX (0,0) - (400,400), 0, -1, 0, 3
    ' copy it
    GRAPHIC COPY hwTempBMP, 0, (0,0) - (50, 50) TO (300, 300)
    ' delete the smaller GW
    GRAPHIC ATTACH hwTempBMP, 0
    GRAPHIC BITMAP END
                                                           
    WHILE skey <> $ESC
        GRAPHIC INKEY$ TO skey
    WEND
END FUNCTION

[Richard Angell]

The "selected graphic target" does not have to be the one you are currently staring at.

Not always. Always it has to be the current GRAPHIC ATTACHed, which could be a BITMAP in memory you will GRAPHIC COPY to.

[Chris Holbrook]

Just in case anyone else was baffled by this problem:

#COMPILE EXE
#DIM ALL

FUNCTION PBMAIN () AS LONG
    LOCAL hwina, hwTemp AS DWORD
    LOCAL skey AS STRING
    
    ' create a GW and fill it with a hatch pattern
    GRAPHIC WINDOW "", 200, 200, 400, 400 TO hwina
    GRAPHIC ATTACH hwina, 0
    GRAPHIC BOX (0,0) - (400,400), 0, -1, 0, 4
    skey = ""
    ' create a temporary GW just big enough to hold the area to be copied
    ' but invisible
    GRAPHIC WINDOW  "", -100, -100, 50, 50 TO hwTemp
    GRAPHIC ATTACH hwTemp, 0
    ' copy the area to the smaller GW
    GRAPHIC COPY hwina, 0, (0,0) - (50, 50) TO (0, 0)
    ' reconnect to the big GW
    GRAPHIC ATTACH hwina, 0
    ' reverse the hatching so the copied area will show up
    GRAPHIC BOX (0,0) - (400,400), 0, -1, 0, 3
    ' copy it
    GRAPHIC COPY hwTemp, 0, (0,0) - (50, 50) TO (300, 300)
    ' delete the smaller GW
    GRAPHIC ATTACH hwTemp, 0
    GRAPHIC WINDOW END
    
    WHILE skey <> $ESC
        GRAPHIC INKEY$ TO skey
    WEND
END FUNCTION

[Chris Holbrook]

Ah, the penny has just dropped. The "selected graphic target" does not have to be the one you are currently staring at.

[Chris Holbrook]

That simply is not correct. You really just need to read the doc and try it.

Been doing that for 90 minutes!

Encouraged by your generous remarks, I will persevere.

[Bob Zale]

That simply is not correct. You really just need to read the doc and try it.

[Chris Holbrook]

You can do that using the GRAPHIC COPY statement. There are 3 syntax options available, the third is the one to use. The help file says:

You can copy a complete bitmap, or a portion of it, to the selected graphic target.

Right, but to stick with high-level GRAPHIC commands, one would have to pull out the bitmap for the whole GRAPHIC WINDOW - potentially huge - just to get the 50x50 portion of it?

[Bob Zale]

You can do that using the GRAPHIC COPY statement. There are 3 syntax options available, the third is the one to use. The help file says:

You can copy a complete bitmap, or a portion of it, to the selected graphic target.

[Chris Holbrook]

Looking at the new GRAPHIC WINDOW stuff, I can copy a bitmap into the GW at a specified location using GRAPHIC COPY, but there is no complementary high-level way of exporting part (say a 50x50 rectangle) of the current GW to a bitmap.

What is the best way to do this?