Display

LEAD Technologies continually reviews and adds file format support to give your application control over the display of almost any Raster or Vector image you encounter. LEADTOOLS currently supports over 150 different image formats and sub formats, each of which has its own unique set of load/save/display options, which may encompass varying types and/or degrees of compression, a range of image information bit-depths, progressive (multi-pass) image display, the ability to maintain multi-page or multi-channel images, animations, or non-image data, just to name a few. You can depend on LEAD Technologies to provide you the support you need to give your application control over the display of almost any image you encounter. Image display can be subdivided into two groups: raster image display and vector image display. These groups are described in more detail in the following sections.

Raster Image Display

LEADTOOLS provides numerous functions to let you take control of your application's image display. Control brightness and contrast settings, color reduction with dithering and palette control, scaling/fitting, enlargement/reduction, panning, scrolling, painting with transparency and/or regions.

Further, LEADTOOLS provides high level image-list and thumbnail browser controls, a special magnifying-glass feature, an automated pan-window control, and a Zoom View control that allows you to annoate pre-defined zoomed regions.

Key Features

Intensity, contrast and gamma correction - LEADTOOLS renders an image of any color depth (1 to 64 bit † ) to any display device, automatically handling any color reduction or expansion. Changes can be applied to the display without affecting the original data. If desired, color reduction and display settings can be rendered into the image (See Image Processing). You can render images with a color specified as transparent.
Dithering - Images can be automatically dithered to match the output display device on the fly, without changing the image in memory. Specify the dithering method for images that have more bits per pixel than the current video mode. The following are options can enhance the quality of your image display:
- Normal dithering (using error diffusion).
- Ordered dithering, faster but less accurate than normal.
- [DLL only] No dithering, which relies on the display device for color reduction.
Position and Scale - Position the displayed image, and zoom in or out (enlarge or reduce) by scaling and clipping. Use nearest neighbor (fastest), bilinear (fast-good quality) or bicubic (best quality) resampling for enlarged/reduced display size. Specify a 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 (fit-to-window preserving aspect ratio, stretch to entire window, fit-to-width, 1:1 normal display).
Display Enhancement - Using our Document and Medical toolkits, when displaying 1-bit (black-and-white) images, to enhance the quality of display you can:
- Specify a scale-to-gray option, which increases the clarity of the 1-bit images when they are scaled (zoomed out).
- Specify a favor-black option, which prevents loss of details, such as fine lines, when an image is scaled down (zoomed out).
- 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.
Automated Controls - When working with the ActiveX, COM, or .NET 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).
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).
Palette Control - If the display mode is 256 colors or less, you can use a palette already associated with the image, or use a fixed palette to eliminate palette (color) shifting when displaying more than one image at a time.
Image List and Thumbnail Browser Controls - Display and manipulate a list of images as an array of thumbnails using the ImageList Control, or use the Thumbnail Browser for browsing entire directories of image files.
Pan Window - The automated pan window enables navigation through a large image using a small thumbnail view.
Zoom View - Our Document and Medical toolkits include a Zoom View control that allows you to display and/or annotate multiple pre-defined zoomed regions.
Regions of Interest - Display an automated rubberband (rectangle, ellipse 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.

Drawing - 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.
Apply Effects - Apply any of over 2000 Special Effects, such as wipes, fades, dissolves, transitions commonly used in slide presentations.
Complete Control - When painting images on any video device, you can:

Vector Image Display

The LEADTOOLS Vector Image Display features provide support for 2D and 3D Vector formats. Support for primitive objects include Arc, Bitmap, Brush, Camera, Circle, Clone, Ellipse, Elliptical Arc, Font, Group, Layer, Line, Pen, Pie, Chord, Poly Draw, Polygon, Poly Line, Poly Bezier, Raster, Rectangle, Text, Vertex and Clipping objects. Vector images can also be rotated, scaled and translated as a whole (not individual objects) for display purposes. In addition there are low and high-level functions to control the view of vector drawings include zooming (both uniform or around any axis), panning, rotation (around any axis) and anti-aliasing. Vector drawings can be scaled to any resolution desired without distorting the original image, ensuring that fine details of the drawing will not be lost during printing.