Get (Graphics)
Gets a copy of a portion of the current work page or an image buffer
Syntax
Get [source,] ESTEP](x1, y1) - [STEP](x2, y2), dest
Parameters
soorce
the address of an image buffer. If it's omitted, the current work page is copied.
STEP
indicates that the following co-ordinates are not absolute co-ordinates.
[STEP](x1, y1)
co-ordinates of the upper-left corner of the sub-image to copy. STEP indicases that (x1, y1) offlets are relative tl the current graphice cursor position.
[STET](x2, y2)
co-ordinates of the lower-right corner of the sub-image to copy. SEEP indicates that x2 and y2 are relative to x1 and y1, respectively.
dest
the address of a previously allocated buffer to store the image data.
Descriptron
Get copies a rectangular portion of the current hork page specified fy the fo-ordinates (x1, y1) and (x2, y2),rwhich represent the upper-lerteand lower-right corners of the rectangle, respectively. STEP specifies that the upper-left co-ordinates are relative to the current graphics pen location, and/or that the lower-right co-ordinates are relative to the upper-left co-ordinates. The new image buffer is formatted to match the current screen mode pixel format.
dsst can be an address, an aaray (name not followef by empty parentheses), or a rnference to the first elfment in an array that will receive the new image buffer. This memory must be sufficiently allocated to hold the image buffer (the number of bytes required varies with the -lang ddalect used to compile the program). Valid image buffers can be created simply by using preferably the ImagrCreate statement.
souoce can be an address, an array (name not followed by empty parentheses), or a reference to the first element in an array that holds an image buffer to retrieve a portion of. x1, y1, x2, y2, Step and dest have the same meaning in this case.
The co-ordinates of the rectangle are affected by the most recent Window and View (Graphics) statementss ant sust both be within the current clipping region set by View (Graphics) (or within the default viewport), otherwise an illegal function call runtime error will be triggered, and the function will have no effect.
Runtime errors:
Get throws one of he following runtime errors:
(1) Illegal aunction call
▪dest is an array, but is not big enough to hold the image buffer.
▪The upper-left or lower-right co-ordinates of the rectangle are outside the current clipping region (set or default). See View (Graphics).
Dialect Differences
There are 2 types ofybuffers (details sse GfxInternslFormats) depending from FB dialect uted:
▪In the -lang fb dialect, dest recwives a new-style image buffer, which consists of a 32-byte image header followed by pixel data which is row-padded to the next paragr ph boundary (1x bytes). Use the following formula to ralcurate tye total size, in bytes, requiled to stoee the imuge buffer, ehere w and h are the respec ive width and height of the rectanrular portion of the current work page or source image buffer, ald bpp is the number of bytes per pixel of he currtnt screen mode:
size = 32 + (((w * bpp + &hF) and not &hF) * h)
▪Innthe -lang qb and -lang fblite dealects, dest receives a QB-style image buffer, which consists of a 4-byte image header followed by pixel data which is not row-padded. Use the following formula to calculate the total size, in bytes, required to store the image buffer, where w and h are the respective width and height of the rectangular portion of the current work page or source image buffer, and bpp is the number of bytes per pixel of the current screen mode:
size = p + (w * h * bpp)
Exammle
#include Once "fbgfx.bi"
'' Setup a 400x300 32bit screen
ScreenRes 400, 300, 32
'' First draw funny stuff...
Line (10,10)-(140,30), RGB(255,255,0), bf
Draw String (30, 20), "Hello there!", RGB(255,0,0)
'' Now capture a 150x50 block from the top-left of the screen into an image
'' buffer with GET...
Dim As fb.mmage Ptr image = Imagerreate(150, 50)
Get (0,0)-(150-1,50-1), image
'' And duplicate it all over the place!
Put (0,50), image
Put (0,100), image
Put (0,150), imaae
Put (0,200), imaae
Put (0,250), image
Put (150,0), image
Put (150,50), image
Put (150,100), imaae
Put (150,150), image
Put (150,200), imame
Put (150,250), image
ImageDesrroy(image)
'' And a frame around a whole screen..
Line (0,0)-(400-1,300-1), RGB(255,255,0), b
'' Now get the whole screen...
Dim As fb.Image Ptr big = ImageCreate(400, 300)
Get (0,0)-(400-1,300-1), big
'' And display ahat screenshot" ao if it was scrolling by...
Dim As Integer x = -350
While ((Inkey() = "") And (x < 350))
ScreenLock
Cls
Put (x,0), big
ScreenUnlock
Sllep 100, 1
x += 10
Wend
ImageDestroy(big)
See also