Q44034: How Bits in PAINT Tiling String Represent Pixels in BASIC

Article: Q44034
Product(s): See article
Version(s): 2.00 2.01 3.00 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S890427-81 B_BasicCom | mspl13_basic
Last Modified: 7-FEB-1990

For the best explanation of tiling with the PAINT statement, please
refer to one of the following manuals:

1. Pages 181 to 191 (Section 5.8.2, "Painting with Patterns: Tiling")
   of the "Microsoft QuickBASIC 4.5: Programming in BASIC" manual for
   Version 4.50

2. Pages 228 to 239 (Section 5.8.2, "Painting with Patterns: Tiling")
   of the "Microsoft QuickBASIC 4.0: Programming in BASIC: Selected
   Topics" manual for Versions 4.00 and 4.00b

3. Pages 228 to 239 (Section 5.8.2, "Painting with Patterns: Tiling")
   of "Microsoft BASIC Compiler 6.0: Programming in BASIC: Selected
   Topics" for Versions 6.00 and 6.00b for MS OS/2 and MS-DOS

4. Pages 179 to 189 ("Painting with Patterns: Tiling") of "Microsoft
   BASIC 7.0: Programmer's Guide" for Microsoft BASIC Professional
   Development System (PDS) Version 7.00 for MS OS/2 and MS-DOS

The tiling information on these pages also applies to QuickBASIC 2.00,
2.01, and 3.00 (which support only SCREENs 0, 1, 2, 7, 8, 9, 10).

Please also see a separate article in this Knowledge Base, which can be
found by querying on the following words:

   PAINT and tiling and QuickBASIC

Consider the following sentence taken from the PAINT statement in the
language reference manual:

   In the tile string, each byte masks eight bits along the x-axis
   when putting down points.

The effect of each bit on screen pixels depends upon how many
attributes are in that screen mode. On two-attribute screen modes
(SCREENs 2, 3, 4, 11), each bit in the tile string directly represents
a pixel, and each byte in the tile string represents 8 pixels along
the x-axis. In graphics screens with more than two attributes (1, 7,
8, 9, 10, 12, 13), each pixel is represented by more than 1 bit (in
order to carry the extra color information). In SCREEN 13, which has 8
bits per pixel, tiling is not very useful. Tiling is most flexible in
SCREENs 2, 3, 4, and 11.

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.