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Bug #746

When using a transparent background, text does not redraw properly when over-written.

Added by Brian Flanagan almost 3 years ago. Updated over 2 years ago.

Status:
Closed
Priority:
Normal
Assignee:
-
Target version:
-
Start date:
05/01/2021
Due date:
% Done:

0%

Estimated time:
1:00 h
Affected version:
1.0.0 (B7)

Description

Example:

Screen Open 0,640,480,32,Lowres
Palette 0,$FFFFFF,$FF0000
Flash Off : Curs Off : Cls 2
Pen 1 : Paper 2 : Locate 0,4
Print "+ for increase"
Print "- for decarease"
Paper 0

Screen Open 1,640,480,32,Lowres
Flash Off : Curs Off : Palette 0,$FFFFFF,$000001
Set Transparent 0 : Cls 0 : Pen 2 : Paper 0
X=0

Do
  Locate 1,1 : Print Using "####";X
  IK$=Inkey$
  If IK$="+" Then X=X+10
  If IK$="-" Then If X >=10 Then X=X-10
  Wait Vbl
Loop

In standard writing mode the text background should be overwritten with the paper color.
In this case, that color is 0 (transparent), but it isn't working.

#1

Updated by David Baldwin almost 3 years ago

This is exactly how I'd expect it to behave. The text is overwritten with the paper, the new text is drawn on the paper. If the paper is transparent, then the new text is drawn directly onto the previous text.

#2

Updated by Francois Lionet almost 3 years ago

  • Status changed from New to Closed

Not a bug, this behavior is normal: AOZ DOES erase the background of the text, but as the color is transparent, you cannot see the erasure.
This is a normal behavior and it is impossible to correct.
;)

#3

Updated by Brian Flanagan over 2 years ago

To Dave & Francois:

Perhaps that's the way it worked in AMOS, but if so, it is not logical.

Consider this analogy:

We have a LITERAL window we're painting on.
Behind this window is a red wall. (The underlying Screen)

If I paint (Print) on the window with white paint (Pen), and with blue paint in the background (Paper),
I will see white letters on a blue background, with nothing showing from the underling wall (Screen).

If I paint (Print) on the window with white paint (Pen), and with transparent "paint" in the background (Paper),
I should see, the white (Pen) text, with the red wall (underlying screen) showing through, since our Paper
color was transparent. (Painting with transparent paint is like scraping the paint off the window when it is used.)

Think about it? How do I paint a transparent color on the window? The only way is by scraping off any existing paint!

Likewise, if my Pen color is transparent, it's like scraping off the paint wherever the text is.

If it is as you say that when you use a transparent color, you can't see an erasure, that doesn't make sense.
After all, what does erasure mean? What happens when you erase a pencil mark? You REMOVE that "ink" from the page,
revealing what is underneath it!

Also, this is NOT impossible to correct! It should be relatively easy.

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