isCOBOL Evolve : Appendices : Library Routines : W$BITMAP
W$BITMAP
The W$BITMAP library routine provides a number of functions to manage images. It recognizes and works with the following image formats: BMP, JPG, GIF, ICO and PNG.
With this library routine it is possible to load and unload (release memory) images, in addition to displaying them. Dealing with too many images can be inefficient. For this reason it is preferable to work with a file known as imagelist. This is a file containing a strip of images. The bitmap is then divided into several images with the size specified and the single image can be referenced by an index representing its position in the bitmap.
The CMYK (Cyan-Magenta-Yellow-Black four inks) color model is not supported. Bitmaps including this model may fail to be loaded, display bad or not be printed correctly. 16-bit bitmaps are also not supported.
Syntax:
 CALL "W$BITMAP" USING opCode
                       parameters
                GIVING bitmapHandle
Parameters:
opCode
Function to be executed. Valid values, defined in isgui.def, are:
 
Destroy an image and releases the memory.
Load an image into memory and then displays it on the screen.
Load an image into memory. The image can then be shown on the GUI or used in print jobs.
Load an image from the client machine into memory. The image can then be shown on the GUI or used in client-side print jobs.
parameters
Parameters depend on the opcode.
Examples:
Example - Load a bitmap from disk and display it
 working-storage section.
 copy "isgui.def".
 77  h-bitmap                pic s9(9) comp-4.
 
 screen section.
 01  Mask.
     03 Bmp1 
        bitmap line 2 col 2
        lines 10 cells size 21 cells
        .
     03 Ef1
        entry-field read-only
        line 13 col 2 size 15 cells
        .
 
 
 procedure division.
 main.
    call "w$bitmap" using wbitmap-load, "images/img.png"
                              giving h-bitmap
    if h-bitmap < 0
       display message "W$BITMAP Error: " h-bitmap
    else
       modify Bmp1 bitmap-handle h-bitmap
    end-if.
    ...