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- M I N I - S C R E E N
- by Dave Moorman
-
-
- MINI-SCREEN is a text-screen
- bitmap display routine the puts Mini-
- Bitmap images on the screen. This is
- an ML module that must be bloaded to
- memory before use. We have included
- two versions -- SCREEN192.ML and
- SCREEN158.ML. The number is the memory
- page to which the module must be
- beloaded.
-
- SYS57812"SCREEN192.ML",dv,0
- POKE780,0 ---
- PO781,0
- POKE782,192
- ---
- SYS65493
- SC=192*256
- ---
-
-
- SETUP
- -----
-
- SYS SC,X,Y,COLOR
-
- where X is the text column
- Y is the text row
- of the upper left corner
- of the mini-screen
- COLOR is the foreground color
- of the mini-screen
-
- The mini-screen needs to be placed
- on the screen with this command. Also,
- a custom font location must be
- established (for instance at Page 56)
- and switched to (by poking 5353272 the
- the appropriate value). The font area
- is where the mini-bitmap files are
- bloaded.
-
-
- CLEAR
- -----
-
- SYS SC+3,SWITCH
-
- where SWITCH is either 0 or 1. If 0,
- the mini-bitmap area is filled with
- 0's -- showing the background color.
- It 1, the area is filled with 1's --
- showing the foreground color. If you
- have already bloaded a mini-bitmap
- file to the font, you will not want to
- do this.
-
-
- PLOT
- ----
-
- SYS SC+6,X,Y,P
-
- where X is the pixel column (0-127)
- Y is the pixel row (0-95)
- P is the pixel to plot (0-1)
-
- Not a very fancy plot routine, but
- servicable.
-
-
- MPLOT
- -----
-
- SYS SC+9,X,Y,P
-
- where X is the pixel column (0-63)
- Y is the pixel row (0-95)
- P is the pixel value (0-3)
-
- This is a multi-color text mode plot.
- When using SETUP, the color must be
- COLOR+8 to enable the MC Text Mode.
- Also, 53280-53282 must be set with the
- three background colors.
-
-
- COPYMEM
- -------
-
- SYS SC+12,FPG,TPG,PGS
-
- where FPG is the From Page
- TPG is the To Page
- PGS is the number of Pages to
- copy.
-
- This is a very fast copymem because
- it doesn't mess around with odd
- numbers of bytes -- copying whole
- pages.
-
-
- With this module, you can build
- your own mini-bitmap screens. A couple
- of secrets:
-
- These bitmaps use all but 64
- characters of the font. So when a
- MINI-BITMAP is made from a SHP or
- Doodle graphics file, the alphanumeric
- characters are only capitals, and all
- reversed. The "blank" screen, except
- where the mini-bitmap is displayed, is
- all CHR$(32)'s, and so is also
- reversed.
-
- Thus, you can have one color for
- the screen, one for the background
- (often the black pixels on the
- screen), and another color for
- non-screen area of the screen. See the
- Cheering Crowd graphic of The Zuccinni
- Song for an example.
-
- Also, in that example, two mini
- screens are placed side by side,
- effectively doubline the "crowd."
-
- We have included a very simple
- Run It program that puts the
- mini-screen on the screen with a
- picture of a Commodorean celebrity.
- Look over the code to understand how
- it works.
-
- This module is at the heart of the
- Zoetrope movies on issue 246 -- and we
- will have more fun with it in the near
- future. If you would like to take a
- crack at making your own movies or
- mini-slide shows -- here is what you
- need.
-
- DMM
-
-
-