Applesoft: Internals--High resolution graphics routines



NOTE:  Regardless of which screen is being displayed, HPAG (location $E6)

determines onto which screen the software draws graphics.  ($20 for HGR, $40

for HGR2)



HGR2            F3D8

Initialize and clear page 2 High-Res.



HGR             F3E2

Initialize and clear page 1 High-Res.



HCLR            F3F2

Clear the current High-Res screen to black.



BKGND           F3F6

Clear the current High-Res screen to last plotted color.



HPOSN           F411

Positions the High-Res cursor without plotting.  HPAG determines which page

the cursor is pointed at.

On entry:

Horizontal = Y,X

  Vertical = A



HPLOT           F457

Call HPOSN then try to plot a dot at the High-Res cursor's position.  The dot

may not be plotted if plotting non-white at a complementary color X

coordinate.



HLIN            F53A

Draws a line from the last plotted point or line destination to the coordinate

in the 6502 registers.

On entry:

Horizontal = X,A

Vertical   = Y



HFIND           F5CB

Convert the High-Res cursor's position to X-Y coordinates.  HFIND allows the

user to tell where on the screen the a shape table left the cursor.

On exit:

$E0 = horizontal lsb

$E1 = horizontal msb

$E2 = vertical



DRAW            F601

Draw the shape pointed to by Y,X using the current HCOLOR starting at the

current High-Res cursor position.  On entry A = rotation factor.



XDRAW           F65D

Draw the shape pointed to by Y,X by starting at the current High-Res cursor

position inverting the existing color of the dots the shape draws over.  On

entry A = rotation factor.



SETHCOL         F6EC

Set the High-Res color to X.  X must be less than 8.



SHLOAD          F775

Loads a shape table into memory from tape above MEMSIZ (HIMEM) and sets the

pointer at $E8.





Apple Tech Notes





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This information is from the Apple Technical Information Library.



ArticleID: TECHINFO-0000081



19960724 15:55:27.00

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