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Topic: Jpg display in bbcbasic4 windows (Read 628 times) |
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larry
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Jpg display in bbcbasic4 windows
« Thread started on: May 12th, 2014, 4:18pm » |
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below is the code I'm using in BBC4win to place a jpg in a window. The Procedure uses an api call.
I want it to display in whatever size the image is. rather than me having to specify the size.
any help would be greatly appreciated
cls
rem maximize window
SW_MAXIMIZE = 3
sys "ShowWindow", @hwnd%, SW_MAXIMIZE
rem Set parematers for loading the jpg onto the window
picture$="i:\jbg\jbg1\00000jb.jpg"
xpos%=0
ypos%=0
xsize%=450
ysize%=600
rem call the procedure that shows the picture to the window
procdisplay(picture$,xpos%,ypos%,xsize%,ysize%)
repeat
rem Wait for keypress
Key%=get
rem Translate key press to action code
case Key% of
when 27 cls:end
otherwise Code%=0
endcase
until Code%<>0
rem this is the procedure that opens and displays the picture
def procdisplay(picture$,xpos%,ypos%,xsize%,ysize%)
local oleaut32%, olpp%, iid%, gpp%, hmw%, hmh%, picture%, res%
sys "LoadLibrary", "OLEAUT32.DLL" to oleaut32%
sys "GetProcAddress", oleaut32%, "OleLoadPicturePath" to olpp%
if olpp%=0 error 100, "Could not get address of OleLoadPicturePath"
dim iid% local 15, picture% local 513
sys "MultiByteToWideChar", 0, 0, picture$, -1, picture%, 256
iid%!0 = &7BF80980
iid%!4 = &101ABF32
iid%!8 = &AA00BB8B
iid%!12 = &AB0C3000
sys olpp%, picture%, 0, 0, 0, iid%, ^gpp%
if gpp% = 0 error 100, "OleLoadPicturePath failed"
sys !(!gpp%+24), gpp%, ^hmw% : rem. IPicture::get_Width
sys !(!gpp%+28), gpp%, ^hmh% : rem. IPicture::get_Height
sys !(!gpp%+32), gpp%, @memhdc%, xpos%, ypos%, xsize%, ysize%, 0, \
\ hmh%, hmw%, -hmh%, 0 to res%
if res% error 100, "IPicture::Render failed"
sys !(!gpp%+8), gpp% : rem. IPicture::Release
sys "InvalidateRect", @hwnd%, 0, 0
sys "UpdateWindow", @hwnd%
endproc
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| « Last Edit: May 12th, 2014, 4:21pm by larry » |
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rtr
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Re: Jpg display in bbcbasic4 windows
« Reply #1 on: May 12th, 2014, 5:58pm » |
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on May 12th, 2014, 4:18pm, larry wrote:| I want it to display in whatever size the image is. rather than me having to specify the size. |
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The easiest way would probably be to take the image dimensions (hmw% and hmh%), convert them from HIMETRIC units to pixels (assume 96 DPI), and then put those values into the xsize% and ysize% variables respectively:
Code: xsize% = INT(hmw% * 96 / 2540 + 0.5)
ysize% = INT(hmh% * 96 / 2540 + 0.5)
Richard.
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