_ICON - QB64 Wiki

_ICON

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The _ICON statement uses an image handle from _LOADIMAGE for the program header and GL icon image in the OS.


Syntax:

_ICON [mainimagehandle&[, smallimagehandle&]]


Parameters:

  • mainimagehandle is the LONG handle value of the OS icon and title bar image pre-loaded with _LOADIMAGE when used alone.
  • smallimagehandle is the LONG handle value of a different title bar image pre-loaded with _LOADIMAGE when used.
  • No image handle designates use of the default QB64 icon or the embedded icon set by $EXEICON.


Description:

  • Older SDL versions must use a valid image handle created by _LOADIMAGE. The default QB64 icon will appear otherwise.
  • In QB64 GL no image handle denotes that the default QB64 program icon should be used.
mainimagehandle will create the image as the icon in the OS and the image in the program header.
smallimagehandle can be used for a different image in the program header bar.
  • The header image will automatically be resized to fit the icon size of 16 X 16 if smaller or larger.
  • Once the program's icon is set, the image can be discarded with _FREEIMAGE.


Errors:

  • NOTE: QB64 SDL does not support icon files! An error will occur using _LOADIMAGE! See Example 2.
  • Images used can be smaller or larger than 32 X 32 pixels, but image resolution may be affected.
  • It is IMPORTANT to free unused or uneeded images with _FREEIMAGE to prevent memory overflow errors!
  • SCREEN 0 text mode requires a 32 bit palette in _LOADIMAGE to load images other than icons as program icons.


Example 1: Loading an image to a 32 bit palette in SCREEN 0 (the default screen mode).

i& =_LOADIMAGE("RDSWU16.BMP",32) '<<<<<<< use your image file name here IF i& < -1 THEN _ICON i& _FREEIMAGE i& ' release image handle after setting icon END IF

Note: _ICON images can be freed if the SCREEN mode stays the same. Freed image handles can on longer be referenced!


Example 2: Function that converts an icon into a temporary bitmap for use in QB64. Function returns the available image count.

SCREEN _NEWIMAGE(640, 480, 256) _TITLE "Icon Converter" icon$ = "daphne.ico" '<<<<<<<<< change icon file name bitmap$ = "tempfile.bmp" indx% = 6 '1 minimum <<<<<<< higher values than count get highest entry image in icon file IF Icon2BMP(icon$, bitmap$, indx%) THEN img& = _LOADIMAGE(bitmap$) ' use 32 as color mode in SCREEN 0 IF img& < -1 THEN ' check that handle value is good before loading _ICON img& ' place image in header _PUTIMAGE (300, 250), img& 'place image on screen _FREEIMAGE img& ' always free unused handles to save memory KILL bitmap$ ' comment out and/or rename to save the bitmaps END IF END IF END ' ---------------------------------------------------- FUNCTION Icon2BMP% (filein AS STRING, fileout AS STRING, index AS INTEGER) 'function creates a bitmap of the icon and returns the icon count DIM byte AS _UNSIGNED _BYTE, word AS INTEGER, dword AS LONG DIM wide AS LONG, high AS LONG, BM AS INTEGER, bpp AS INTEGER rf = FREEFILE IF LCASE$(RIGHT$(filein, 4)) = ".ico" THEN 'check file extension is ICO only OPEN filein FOR BINARY ACCESS READ AS rf ELSE EXIT FUNCTION END IF GET rf, , word GET rf, , word: icon = word GET rf, , word: count = word IF icon <> 1 OR count = 0 THEN CLOSE rf: EXIT FUNCTION 'PRINT icon, count IF index > 0 AND index <= count THEN entry = 16 * (index - 1) ELSE entry = 16 * (count - 1) SEEK rf, 1 + 6 + entry 'start of indexed Entry header GET rf, , byte: wide = byte ' use this unsigned for images over 127 GET rf, , byte: high = byte ' use this unsigned because it isn't doubled GET rf, , word 'number of 4 BPP colors(256 & 32 = 0) & reserved bytes GET rf, , dword '2 hot spots both normally 0 in icons, used for cursors GET rf, , dword: size = dword 'this could be used, doesn't seem to matter GET rf, , dword: offset = dword 'find where the specific index BMP header is 'PRINT wide; "X"; high, size, offset SEEK rf, 1 + offset + 14 'only read the BPP in BMP header GET rf, , word: bpp = word IF bpp = 0 THEN CLOSE rf: EXIT FUNCTION IF bpp <= 24 THEN pixelbytes = bpp / 8 ELSE pixelbytes = 3 IF bpp > 1 AND bpp <= 8 THEN palettebytes = 4 * (2 ^ bpp) ELSE palettebytes = 0 datasize& = (wide * high * pixelbytes) + palettebytes 'no padder should be necessary filesize& = datasize& + 14 + 40 ' data and palette + header bmpoffset& = palettebytes + 54 ' data offset from start of bitmap readbytes& = datasize& + 28 ' (40 - 12) bytes left to read in BMP header and XOR mask only 'PRINT bpp, bmpoffset&, filesize& BM = CVI("BM") 'this will create "BM" in file like MKI$ would wf = FREEFILE OPEN fileout FOR BINARY AS wf PUT wf, , BM PUT wf, , filesize& dword = 0 PUT wf, , dword PUT wf, , bmpoffset& 'byte location of end of palette or BMP header dword = 40 PUT wf, , dword ' start of 40 byte BMP header PUT wf, , wide PUT wf, , high SEEK rf, 1 + offset + 12 ' after 12 bytes start copy of BMP header starting at planes dat$ = STRING$(readbytes&, 0) 'create string to hold remaining bytes needed w/o AND mask data GET rf, , dat$ ' copy lower header, palette(if used) and XOR mask PUT wf, , dat$ ' put all of the string data in the bitmap all at once CLOSE rf, wf Icon2BMP = count ' return the number of icons available in the icon file END FUNCTION

Code by Ted Weissgerber
Note: Once the file has been loaded into memory, the image handle can still be used even after the file has been deleted.


See also:



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