Difference between revisions of "LOADIMAGE"

From QB64 Wiki
Jump to navigation Jump to search
imported>SMcNeill
imported>SMcNeill
(style guidelines)
Line 1: Line 1:
 
{{DISPLAYTITLE:_LOADIMAGE}}
 
{{DISPLAYTITLE:_LOADIMAGE}}
The '''_LOADIMAGE''' function loads an image into memory and returns valid [[LONG]] image handle values that are less than -1.  
+
The [[_LOADIMAGE]] function loads an image into memory and returns valid [[LONG]] image handle values that are less than -1.  
  
  
 
{{PageSyntax}}
 
{{PageSyntax}}
:: handle& = '''_LOADIMAGE& ('''''filename$''[, ''mode&'']''')'''
+
: {{Parameter|handle&}} = [[_LOADIMAGE&]]({{Parameter|filename$}}[, {{Parameter|mode%}}])
  
  
 
{{Parameters}}
 
{{Parameters}}
* ''filename'' is literal or variable [[STRING]] file name value.
+
* {{Parameter|filename$}} is literal or variable [[STRING]] file name value.
* Optional ''mode'' [[INTEGER]] values can be any valid screen mode except zero, 256 color, 32 bit or 33 hardware image.
+
* Optional {{Parameter|mode%}} [[INTEGER]] values can be any valid screen mode except zero, 256 color, 32 bit or 33 hardware image.
  
  
 
{{PageDescription}}
 
{{PageDescription}}
 
* File types supported:  BMP, JPG, PNG, GIF, PNM, XPM, XCF, PCX, TIF, LBM, and TGA. A path can also be given.
 
* File types supported:  BMP, JPG, PNG, GIF, PNM, XPM, XCF, PCX, TIF, LBM, and TGA. A path can also be given.
* The ''mode&'' can designate 256(8 bit), 32 bit color or 33 ('''version 1.000 and up'''). Omit to use the current graphic screen settings.
+
* The {{Parameter|mode%}} can designate 256 (8 bit), 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''').
 
* 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.
 
* 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]].
 
* 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 could not load the image. Valid {{KW|LONG}} handle returns are less than -1.
+
* 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.
+
* 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]].'''
 
*  '''Images are not deallocated when the [[SUB]] or [[FUNCTION]] they are created in ends. Free them with [[_FREEIMAGE]].'''
  
  
 
{{PageErrors}}
 
{{PageErrors}}
* Some picture file images may not load when a ''mode'' value is designated. Try loading it without a ''mode'' designation.
+
* 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!'''
+
* '''It is IMPORTANT to free unused or discarded images with [[_FREEIMAGE]] to prevent CPU memory overflow errors.'''
* '''In text [[SCREEN]] 0 ''mode&'' 32 must be designated!''' When loading an [[_ICON]] image use 32 for the mode also.
+
* '''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.  
 
''Example 1:''  Already in SCREEN 13 and want computer to match the 32-bit jpg/etc.  
 
colors to the current palette:
 
colors to the current palette:
Line 83: Line 84:
  
  
''See Examples:''
+
===More examples===
 
* [[SAVEIMAGE]] (QB64 Image to Bitmap SUB by Galleon)
 
* [[SAVEIMAGE]] (QB64 Image to Bitmap SUB by Galleon)
 
+
* [[Program ScreenShots]] (Member-contributed program for legacy screen modes)
* [[Program ScreenShots]] (Member program for legacy screen modes)
 
 
 
 
* [[ThirtyTwoBit SUB]] (QB64 Image area to bitmap)
 
* [[ThirtyTwoBit SUB]] (QB64 Image area to bitmap)
  
  
 
{{PageSeeAlso}}
 
{{PageSeeAlso}}
* [[_FREEIMAGE]], [[_ICON]] {{text|('''version 1.000 and up''')}}
+
* [[_FREEIMAGE]], [[_ICON]]
 
* [[_PUTIMAGE]], [[_MAPTRIANGLE]]
 
* [[_PUTIMAGE]], [[_MAPTRIANGLE]]
 
* [[_NEWIMAGE]], [[_COPYIMAGE]]  
 
* [[_NEWIMAGE]], [[_COPYIMAGE]]  

Revision as of 02:27, 6 September 2017

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 any valid screen mode except zero, 256 color, 32 bit or 33 hardware image.


Description

  • File types supported: BMP, JPG, PNG, GIF, PNM, XPM, XCF, PCX, TIF, LBM, and TGA. A path can also be given.
  • The mode% can designate 256 (8 bit), 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: Already in SCREEN 13 and want computer to match the 32-bit jpg/etc. colors to the current palette:

SCREEN 13 i& = _LOADIMAGE("mypic.jpg") _PUTIMAGE, i&


Example 2: Already in SCREEN 13 but want to load an 8-bit image and adopt its palette as the current palette:

SCREEN 13 i& = _LOADIMAGE("mypic256col.bmp", 256) _COPYPALETTE i&, 0 _PUTIMAGE, i&


Example 3: Want to display an image in 32-bit color using its resolution as a program screen:

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


Example 4: 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$ > ""

Code by Ted Weissgerber
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


See also



Navigation:
Go to Keyword Reference - Alphabetical
Go to Keyword Reference - By usage
Go to Main WIKI Page