Setting up picture lists
You can add pictures to the regular and state picture lists in the
painter or during execution. During execution, you can assign pictures
in the regular picture list to the overlay list.
Mask color
The mask color is a color used in the picture that becomes
transparent when the picture is displayed. Usually you should pick the
picture’s background color so that the picture blends with the color of
the TreeView.
Before you add a picture, in the painter or in a script, you can
set the mask color to a color appropriate for that picture. This
statement sets the mask color to white, which is right for a picture
with a white background:
|
1 |
tv_1.PictureMaskColor = RGB(255, 255, 255) |
Each picture can have its own mask color. A picture uses the color
that is in effect when the picture is inserted. To change a picture’s
mask color, you have to delete the picture and add it again.
Image size
In the painter you can change the image size at any time by
setting the Height and Width properties on each picture tab. All the
pictures in the list are scaled to the specified size.
During execution, you can change the image size for a picture list
only when that list is empty. The DeletePictures and
DeleteStatePictures functions let you clear the lists.
Example
This sample code illustrates how to change properties and add
pictures to the regular picture list during execution. Use similar code
for state pictures:
|
1 2 3 4 5 6 7 8 9 10 |
tv_list.DeletePictures() tv_list.PictureHeight = 32 tv_list.PictureWidth = 32 tv_list.PictureMaskColor = RGB(255,255,255) tv_list.AddPicture("c:apps_pbkelly.bmp") tv_list.PictureMaskColor = RGB(255,0,0) tv_list.AddPicture("Custom078!") tv_list.PictureMaskColor = RGB(128,128,128) tv_list.AddPicture("Custom044!") |
Deleting pictures and how it affects
existing items
Deleting pictures from the picture lists can have an unintended
effect on item pictures being displayed. When you delete pictures, the
remaining pictures in the list are shifted to remove gaps in the list.
The remaining pictures get a different index value. This means items
that use these indexes get new images.
Deleting pictures from the regular picture list also affects the
overlay list, since the overlay list is not a separate list but points
to the regular pictures.
To avoid unintentional changes to item pictures, it is best to
avoid deleting pictures after you have begun using picture indexes for
items.