_LOADIMAGE
The _LOADIMAGE function loads an image into memory and returns valid LONG image handle values that are less than -1.
Syntax
- handle& = _LOADIMAGE(filename$[, mode%])
Parameters
- filename$ 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 - 1 and _HEIGHT - 1.
- Images can be made into a program SCREEN 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.
Errors
- 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.
Examples
Example 1: To display an image in 32-bit color using its resolution as a program screen:
i& = _LOADIMAGE("mypic.jpg", 32) SCREEN i&
Example 2: 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: The QB64.PNG file picturing the QB64 bee can saved from the top of the QB64 forum. 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)
See also
- _FREEIMAGE, _ICON
- _PUTIMAGE, _MAPTRIANGLE
- _NEWIMAGE, _COPYIMAGE
- _PRINTIMAGE (printer)
- _PALETTECOLOR (function), _COPYPALETTE, _ICON
- SCREEN (statement)
- Hardware images
- Bitmaps, Icons and Cursors, GIF Images