Get and set properties that control the behavior of
the paint functions.Image Display
Take control of your application's image display. With LEADTOOLS, you control brightness and contrast settings, color reduction with dithering and palette control, zooming/scaling/fitting, panning, scrolling, painting with transparency and/or regions. Additionally, LEADTOOLS provides image-list and thumbnail browser controls, a special magnifying-glass feature, as well as an automated pan-window control.
LEADTOOLS renders an image of any color depth (1 to 64 bit**) to any display device, automatically handling any color reduction or expansion. Use nearest neighbor (fastest), bilinear (fast-good quality) or bicubic (best quality) resampling for zoomed display of images. Images can be automatically dithered to match the output display device on the fly, without changing the image in memory. Intensity, contrast and gamma correction changes can be applied to the display without affecting the original data. (AdditionalIy, the color reduction and display settings can be rendered into the image if desired, see Image Processing) Images can be scaled, zoomed, or scrolled when displayed. You can render images with a color specified as transparent.
You can position the displayed image, and zoom in or out by scaling and clipping the display. The rotated display* feature allows rendering images rotated in 90-degree increments without changing the image in memory. Large 1-bit images can remain compressed in memory while decompressing only the portion needed for display*. On a 256-color device, you can use a fixed palette option to eliminate palette shifting when displaying more than one image at a time. An automated pan window is provided to enable navigation on a large image using a small thumbnail view. LEADTOOLS also lets you display and manipulate a list of images as an array of thumbnails using the ImageList Control. In addition, LEADTOOLS provides a Thumbnail Browser for browsing entire directories of image files.
When working with .NET and COM controls, you can set properties which determine the way that images are displayed in the control, such as AutoScroll (automated scroll bars), AutoSize (snap control to image), PaintSizeMode (1:1 scale, fit image to control, zoomed at specified magnification factors etc.)
LEADTOOLS Document/Medical toolkits include specialized display filters including favor black and scale to gray, which allow you to enhance and "clean up" 1 bit images. LEADTOOLS Medical Imaging display support adds 9-16 bit grayscale, and 12 and 16 bit display with window leveling.
When painting images on any video device, you can:
Get and set properties that control the behavior of
the paint functions.
Control the brightness, contrast, and gamma correction
when painting (without affecting the bitmap).
Define the client area of a LEAD control as a display
surface where you can use Windows graphics device interface (GDI) functions
for drawing or adding text. (You can also get a display surface derived
from the actual image stored in memory in order to use Windows GDI to
draw permanently into the image - see Image Processing: Drawing).
Display an automated rubberband (rectangle, elipse
or freehand) to mark an area and create a region of interest.
Paint an image only in a selected region of interest,
or paint an image with transparency (any pixels which are the selected
transparent color are not painted).
Zoom in on a selected area. Use with automated rubberbanding
for entirely automated behavior, or specify selected area in code.
Selectively force repainting of the image in a LEAD
control to avoid unecessary repaints, or use AutoRepainting to automate
all display updates.
Scale and position the image - specify source rectangle
(portion of source image to paint) and destination rectangle (position
on screen or drawing surface on which to paint it) for complete control
over image zoom and position, or specify higher level properties like
ZoomFactor or PaintMode (fit-to-window preserving aspect ratio, stretch
to entire window, fit-to-width, 1:1 normal display, etc.). When used with
the AutoScroll option, all Scroll Bar activity is automatic (scroll bars
respond to programmatic changes of display settings, and display settings
are updated by user's use of scroll bars).
Limit the area to be painted by specifying the source
and destination clipping areas (independent of source and destination
rectangles which position image on screen).
Apply any of over 2000 special effects, such as wipes,
fades, dissolves, transitions commonly used in slide presentations.
Apply ROP codes, which determine how to interact with
the existing image on the screen.
Use a buffer as the source to paint. (Can be used,
for example, to paint an image as it is being loaded)
Specify an option for fast painting (without device
error checking).
Use Double Buffer painting to eliminate flicker when
painting.
Load CMYK images and paint them to the device context.
The data is kept in memory until the actual paint.
Create and display animations (using bitmap lists).
If the display mode is 256 colors or less, you can:
Use the palette associated with the image (if palletized),
or use a fixed palette. You can specify LEAD's fixed palette or the Netscape
fixed palette. Fixed palettes allow you to display multiple images on
a screen in 256 color mode without "color shifting".
Specify the dithering method, for images that have
more bits per pixel than the current video mode. The following are possible
options:
Normal dithering (using error diffusion).
Ordered dithering, which is faster but less accurate
than normal.
No dithering, which relies on the display device for
color reduction.
To enhance the display quality of 1-bit (black-and-white) images, you can:
Specify a scale-to-gray option, which increases the
clarity of the 1-bit images when they are scaled (zoomed in or zoomed
out).
Specify a favor-black option, which prevents loss
of details, such as fine lines, when an image is scaled down (zoomed out).
Supported Platforms