qb64/internal/help/_LOADIMAGE.txt

{{DISPLAYTITLE:_LOADIMAGE}}
The [[_LOADIMAGE]] function loads an image into memory and returns valid [[LONG]] image handle values that are less than -1. 


{{PageSyntax}}
: {{Parameter|handle&}} = [[_LOADIMAGE]]({{Parameter|filename$}}[, {{Parameter|mode%}}])


{{Parameters}}
* {{Parameter|filename$}} is literal or variable [[STRING]] file name value.
* Optional {{Parameter|mode%}} [[INTEGER]] values can be:
** 256 = 8-bit (256-color, ''QB64 versions prior to 1.000'')
** 32 = 32-bit
** 33 = hardware image


{{PageDescription}}
* Various common image file formats supported, like BMP, JPG, PNG, etc. A path can also be given.
* The {{Parameter|mode%}} can designate 256 (8-bit - versions prior to 1.000), 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)|_WIDTH]] - 1 and [[_HEIGHT]] - 1.
* Images can be made into a program [[SCREEN (statement)|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 ({{Parameter|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]].'''


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


{{PageExamples}}
''Example 1:''  Already in SCREEN 13 and want computer to match the 32-bit jpg/etc. 
colors to the current palette:
{{CodeStart}} '' ''
{{Cl|SCREEN (statement)|SCREEN}} 13
i& = {{Cl|_LOADIMAGE}}("mypic.jpg") 
{{Cl|_PUTIMAGE}}, i& '' ''
{{CodeEnd}}


''Example 2:'' Already in SCREEN 13 but want to load an 8-bit image and adopt its 
palette as the current palette:
{{CodeStart}} '' ''
{{Cl|SCREEN (statement)|SCREEN}} 13
i& = {{Cl|_LOADIMAGE}}("mypic256col.bmp", 256)
{{Cl|_COPYPALETTE}} i&, 0
{{Cl|_PUTIMAGE}}, i& '' ''
{{CodeEnd}}


''Example 3:'' Want to display an image in 32-bit color using its resolution as a program screen:
{{CodeStart}} '' ''
i& = {{Cl|_LOADIMAGE}}("mypic.jpg", 32)
{{Cl|SCREEN (statement)|SCREEN}} i& '' ''
{{CodeEnd}}


''Example 4:'' [[DRAW]]ing and rotating an image 360 degrees using Turn Angle. [[POINT]] is used to read the invisible image source.
{{CodeStart}}
{{Cl|SCREEN (statement)|SCREEN}} {{Cl|_NEWIMAGE}}(800, 600, 32)
img& = {{Cl|_LOADIMAGE}}("QB64.PNG")                           'load the image file to be drawn

wide% = {{Cl|_WIDTH (function)|_WIDTH}}(img&): deep% = {{Cl|_HEIGHT}}(img&)
TLC$ = "BL" + {{Cl|STR$}}(wide% \ 2) + "BU" + {{Cl|STR$}}(deep% \ 2)  'start draw at top left corner
RET$ = "BD BL" + {{Cl|STR$}}(wide%)                            'return to left side of image
{{Cl|_SOURCE}} img&
{{Cl|_DEST}} 0
DO
  {{Cl|FOR...NEXT|FOR}} angle% = 0 {{Cl|TO}} 360 {{Cl|STEP}} 15
    {{Cl|CLS}}
    {{Cl|DRAW}} "BM400, 300" + "TA=" + {{Cl|VARPTR$}}(angle%) + TLC$
    {{Cl|FOR...NEXT|FOR}} y = 0 {{Cl|TO}} deep% - 1
      {{Cl|FOR...NEXT|FOR}} x = 0 {{Cl|TO}} wide% - 1
        {{Cl|DRAW}} "C" + {{Cl|STR$}}({{Cl|POINT}}(x, y)) + "R1"            'color and DRAW each pixel
      {{Cl|NEXT}}
      {{Cl|DRAW}} RET$
    {{Cl|NEXT}}
    {{Cl|_DISPLAY}}                         'NOTE: CPU usage will be HIGH!
  {{Cl|NEXT}}
{{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|INKEY$}} > "" '' ''
{{CodeEnd}}
{{small|Code by Ted Weissgerber}}
:''NOTE:'' The ''QB64.PNG'' file picturing the QB64 bee can saved from the top of the [http://www.qb64.net/forum/index.php 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)


{{PageSeeAlso}}
* [[_FREEIMAGE]], [[_ICON]]
* [[_PUTIMAGE]], [[_MAPTRIANGLE]]
* [[_NEWIMAGE]], [[_COPYIMAGE]] 
* [[_PRINTIMAGE]] (printer)
* [[_PALETTECOLOR (function)]], [[_COPYPALETTE]], [[_ICON]]
* [[SCREEN (statement)]]
* [[Hardware images]]
* [[Bitmaps]], [[Icons and Cursors]], [[GIF Images]]


{{PageNavigation}}