Crestron TPMC-8X-GA, Руководство по эксплуатации

Страница: 46 / 66

Isys
®
8.4” WiFi Touch Screen Crestron TPMC-8X-GA
A 16-bit highcolor system is considered sufficient to provide life-like colors. It is
encoded using 5-bits to represent red, 5-bits to represent blue and (since the human
eye is more sensitive to the color green) 6-bits to represent 64 levels of green. These
can therefore be combined to provide 65,536 mixed colors (32 x 32 x 64 = 65,536).
In a 24-bit graphics display, the video memory allocates 24 bits for each pixel on the
screen enabling each pixel to take on any one of a possible 16.7 million colors. Each
24-bit value is composed of 8-bits for red, 8-bits for green and 8-bits for blue. These
triplets of 8-bit values are also referred to as the red, green and blue color planes. A
24-bit image is actually composed of three component images which combine to
create the truecolor picture. The reason this is called truecolor is that this is near the
maximum number of colors the human eye is able to detect.
Truecolor images are sometimes represented by a 32-bit value. The extra 8-bits do
not enhance the precision of the color representation but act as an alpha channel that
represents pixel translucence. The 32-bit truecolor has become popular on the
computer desktop to provide effects such as translucent windows, fading menus and
shadows.
In graphics intensive applications such as touch screens, raising or lowering the color
depth of the displayed graphics can achieve a balance of performance and quality.
Lower color depths do not require as much frame buffer memory or display
bandwidth, allowing them to be generated and displayed more quickly. Increasing
color depth results in higher color quality at the expense of display speed and
responsiveness. By using mostly 8-bit or 16-bit graphics and holding 32-bit graphics
to a minimum (e.g. for a family photo, etc.), a sophisticated project can be created
that fits in the memory space provided while the touch screen remains very
responsive.
Relationship of Bits to Colors
NUMBER OF BITS NUMBER OF COLORS
1 bit Black and White
2 bits 4 Colors
4 bits 16 Colors
8 bits 256 Colors
16 bits 65,536 Colors (Highcolor)
24 bits 16.7 million Colors (Truecolor)
32 bits 16.7 million Colors plus Transparency
When creating a VT Pro-e project, the image size can be compressed and reduced in
the “Page Properties” dialog box for the entire page. The image size can also be
compressed and reduced using the “Image Properties” dialog box. A reduction in
image size saves a considerable amount of memory space for the project.
In VT Pro-e, the Compress checkbox permits the image to be compressed when
compiling. The 16 Bits checkbox converts a 24-bit or 32-bit image to 16 bits. This
conversion to a 16-bit image may cause the loss of some subtle shading. To
compensate for this, use the dithering to simulate the original shading. Check the
image with each of the available dithering types to determine which delivers the best
quality image.
Dithering type selection can be accessed from the “Page Properties” or “Image
Properties” dialog boxes in VT-Pro-e. Refer to the following illustrations.
42
•
Isys
®
8.4” WiFi Touch Screen: TPMC-8X-GA Operations Guide – DOC. 7078E