Using the BITMAP control, a user can place a bitmap on the screen. The effect is similar to using the W$BITMAP library routine. However, with the BITMAP control, your bitmap can be animated.
To display a bitmap, you must first load it with the W$BITMAP library routine, using the WBITMAP-LOAD option (see Book 4, Appendix I). This operation retrieves the bitmap from disk and loads it into memory. The process is identical to loading bitmaps for bitmap push buttons.
Common Properties
TITLE
Bitmaps do not have titles.
VALUE
A bitmap does not have a value.
SIZE
SIZE and LINES are measured in pixels. The specified number of pixels are displayed, starting from the upper left-hand corner of the bitmap (for an exception to this, see the BITMAP-NUMBER special property below). If SIZE and LINES are not specified, then the entire bitmap is used.
COLOR
This property is ignored. The bitmap is displayed using the colors encoded in the image.
Special Properties
BITMAP-HANDLE (numeric) This property indicates the bitmap to display. The value must correspond to the bitmap handle returned by the WBITMAP-LOAD option of W$BITMAP. If this value is omitted, then the control uses the bitmap most recently loaded by W$BITMAP.
BITMAP-NUMBER (numeric) Use this property to display an image from a bitmap strip. A bitmap strip is a series of images of equal width that are strung together horizontally in a single bitmap file. The value of this property is the number of the image in the strip, beginning on the left with "1". You can identify a particular image if you specify the width of the logical image with the SIZE phrase and the number of the image with the BITMAP-NUMBER property. The default value for this property is "1".
BITMAP-NUMBER is updated by the runtime to reflect the current image shown when an animated bitmap is displayed. You can retrieve this value with the INQUIRE verb.
BITMAP-START, BITMAP-END (both numeric) These properties are used when you want to animate a bitmap. Like BITMAP-NUMBER, the value of BITMAP-START is the number of a particular image in a bitmap strip, specifically, the first one to use during animation. Animation runs sequentially in the strip from BITMAP-START to BITMAP-END, looping back to BITMAP-START. If BITMAP-START is not set smaller than BITMAP-END, the control sets BITMAP-START equal to BITMAP-END. The default value for each property is "1".
BITMAP-TIMER (numeric) This property is used for bitmap animation. Its value is the amount of time each bitmap image is displayed during animation, in hundredths of seconds. When this property is set to "0", the bitmap is not animated. Setting the property to a negative value has an undefined effect.