SAVEIMAGE: Difference between revisions
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* All attempts are made to ensure the image is saved in the best possible quality in 32-bit RGBA format. Alpha channel information is preserved wherever the format allows. | * All attempts are made to ensure the image is saved in the best possible quality in 32-bit RGBA format. Alpha channel information is preserved wherever the format allows. | ||
* SCREEN 0 (text mode) screen and "images" can also be saved. Text surfaces are internally rendered using the master QB64-PE VGA fonts before saving. | * SCREEN 0 (text mode) screen and "images" can also be saved. Text surfaces are internally rendered using the master QB64-PE VGA fonts before saving. | ||
{{PageAvailability}} | |||
<!-- QB64 = a version or none, QBPE = a version or all, Platforms = yes or no --> | |||
<gallery widths="48px" heights="48px" mode="nolines"> | |||
File:Qb64.png|'''none''' | |||
File:Qbpe.png|'''v3.9.0''' | |||
File:Apix.png | |||
File:Win.png|'''yes''' | |||
File:Lnx.png|'''yes''' | |||
File:Osx.png|'''yes''' | |||
</gallery> | |||
<!-- Additional availability notes go below the gallery, e.g. --> | |||
Revision as of 08:18, 5 October 2023
_SAVEIMAGE saves the contents of an image or screen page to an image file.
Syntax
- _SAVEIMAGE fileName$[, imageHandle&][, requirements$]
Parameters
- fileName$ is literal or variable STRING file name value.
- Optional imageHandle& is a LONG image handle or a valid screen page number.
- Optional requirements$ STRING values can be:
- PNG: Saves the image as Portable Network Graphics format if no file extension is specified.
- QOI: Saves the image as Quite OK Image format if no file extension is specified.
- BMP: Saves the image as Windows Bitmap format if no file extension is specified.
- TGA: Saves the image as Truevision TARGA format if no file extension is specified.
- JPG: Saves the image as Joint Photographic Experts Group format if no file extension is specified.
- HDR: Saves the image as Radiance HDR format if no file extension is specified.
Description
- fileName$ extension name takes precedence over requirements$
- If no file extension is specified in fileName$ and no format is specified in requirements$, then the PNG format is used by default.
- If imageHandle& is omitted then the image handle returned by _DISPLAY (function) is used.
- All attempts are made to ensure the image is saved in the best possible quality in 32-bit RGBA format. Alpha channel information is preserved wherever the format allows.
- SCREEN 0 (text mode) screen and "images" can also be saved. Text surfaces are internally rendered using the master QB64-PE VGA fonts before saving.
Availability
none
v3.9.0
yes
yes
yes
Examples
Example 1: Using _SAVEIMAGE with SCREEN 0.
OPTION _EXPLICIT CONST X_MIN = -2! CONST X_MAX = 1! CONST Y_MIN = -1! CONST Y_MAX = 1! CONST MAX_ITER = 100 CONST PIX_CHAR = 48 SCREEN 0 WIDTH 160, 100 _FONT 8 DIM w AS LONG: w = _WIDTH DIM h AS LONG: h = _HEIGHT DIM maxX AS LONG: maxX = w - 1 DIM maxY AS LONG: maxY = h - 1 DIM y AS LONG: FOR y = 0 TO maxY DIM x AS LONG: FOR x = 0 TO maxX DIM cx AS SINGLE: cx = X_MIN + (x / w) * (X_MAX - X_MIN) DIM cy AS SINGLE: cy = Y_MIN + (y / h) * (Y_MAX - Y_MIN) DIM zx AS SINGLE: zx = 0 DIM zy AS SINGLE: zy = 0 DIM i AS LONG: i = 0 DO UNTIL zx * zx + zy * zy >= 4 OR i >= MAX_ITER DIM temp AS SINGLE: temp = zx * zx - zy * zy + cx zy = 2 * zx * zy + cy zx = temp i = i + 1 LOOP COLOR i MOD 16 _PRINTSTRING (x + 1, y + 1), CHR$(PIX_CHAR) NEXT x NEXT y _SAVEIMAGE "TextMandelbrot!.jpg" END |
- Explanation: Draws a Mandelbrot in SCREEN 0 and then saves the screen as a .jpg image
Example 2: Saving a graphics image to a .png file using _SAVEIMAGE.
OPTION _EXPLICIT CONST X_MIN = -2! CONST X_MAX = 1! CONST Y_MIN = -1! CONST Y_MAX = 1! CONST MAX_ITER = 100 DIM img AS LONG: img = _NEWIMAGE(640 * 2, 400 * 2, 256) _DEST img DIM w AS LONG: w = _WIDTH DIM h AS LONG: h = _HEIGHT DIM maxX AS LONG: maxX = w - 1 DIM maxY AS LONG: maxY = h - 1 DIM y AS LONG: FOR y = 0 TO maxY DIM x AS LONG: FOR x = 0 TO maxX DIM cx AS SINGLE: cx = X_MIN + (x / maxX) * (X_MAX - X_MIN) DIM cy AS SINGLE: cy = Y_MIN + (y / maxY) * (Y_MAX - Y_MIN) DIM zx AS SINGLE: zx = 0 DIM zy AS SINGLE: zy = 0 DIM i AS LONG: i = 0 DO UNTIL zx * zx + zy * zy >= 4 OR i >= MAX_ITER DIM temp AS SINGLE: temp = zx * zx - zy * zy + cx zy = 2 * zx * zy + cy zx = temp i = i + 1 LOOP PSET (x, y), (i MOD 16) * 16 + (i MOD 8) NEXT x NEXT y _SAVEIMAGE "Mandelbrot", img _DEST 0 PRINT "Saved image." END |
- Explanation: This is like example one. However, it renders the graphics to an 8-bit offscreen image and then passes the image handle to _SAVEIMAGE.