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QB64 is a modern extended BASIC programming language that retains QBasic/QuickBASIC 4.5 compatibility and compiles native binaries for Windows, Linux, and macOS.

The _LOADIMAGE function loads an image into memory and returns valid LONG image handle values that are less than -1.

Syntax

handle& = _LOADIMAGE(filename$[, mode%])

Parameter(s)

filename$ is literal or variable STRING file name value.
Optional mode% INTEGER values can be:
- 32 = 32-bit
- 33 = hardware image

Description

Various common image file formats supported, like BMP, JPG, PNG, etc. A path can also be given.
The mode% can designate 32-bit color or 33 (version 1.000 and up). Omit to use the current graphic screen settings.
Mode 33 images are hardware accelerated and are created using _LOADIMAGE or _COPYIMAGE (version 1.000 and up).
Loaded images can be read invisibly using POINT. Image coordinates start at 0 up to the _WIDTH (function) - 1 and _HEIGHT - 1.
Images can be made into a program SCREEN (statement) or page adopting the size and palette settings or placed using _PUTIMAGE.
Returns -1 as an invalid handle if it can’t load the image. Valid LONG handle returns are less than -1 (handle& < -1).
Valid images only need to be loaded once. The handle can be used repeatedly until freed.
Images are not deallocated when the SUB or FUNCTION they are created in ends. Free them with _FREEIMAGE.

Error(s)

Some picture file images may not load when a mode% value is designated. Try loading it without a mode% designation.
It is important to free unused or discarded images with _FREEIMAGE to prevent CPU memory overflow errors.
In text-only SCREEN 0, mode% 32 must be specified. When loading an _ICON image use 32 for the mode% too.

Example(s)

To display an image in 32-bit color using its resolution as a program screen:

i& = _LOADIMAGE("mypic.jpg", 32)
SCREEN i& 

DRAWing and rotating an image 360 degrees using Turn Angle. POINT is used to read the invisible image source.

SCREEN _NEWIMAGE(800, 600, 32)
img& = _LOADIMAGE("QB64.PNG")                           'load the image file to be drawn

wide% = _WIDTH(img&): deep% = _HEIGHT(img&)
TLC$ = "BL" + STR$(wide% \ 2) + "BU" + STR$(deep% \ 2)  'start draw at top left corner
RET$ = "BD BL" + STR$(wide%)                            'return to left side of image
_SOURCE img&
_DEST 0
DO
  FOR angle% = 0 TO 360 STEP 15
    CLS
    DRAW "BM400, 300" + "TA=" + VARPTR$(angle%) + TLC$
    FOR y = 0 TO deep% - 1
      FOR x = 0 TO wide% - 1
        DRAW "C" + STR$(POINT(x, y)) + "R1"            'color and DRAW each pixel
      NEXT
      DRAW RET$
    NEXT
    _DISPLAY                         'NOTE: CPU usage will be HIGH!
  NEXT
LOOP UNTIL INKEY$ > "" 

NOTE: Speed varies with image size.

More examples

SAVEIMAGE (QB64 Image to Bitmap SUB by Galleon)
Program ScreenShots (Member-contributed program for legacy screen modes)
ThirtyTwoBit SUB (QB64 Image area to bitmap)