Clear text area or graphics area

[Ivan]

Is it possible to clear only text area or clear only graphics area?

REM graphics_window
VDU 24,0,0,1847,1400

REM text_window
VDU 28,0,5,80,0

PRINT TAB(0,0)"CLS test"

MOVE 50,50
DRAW 1200,50

[KenDown]

Yes.

Code: Select all

      VDU28,10,40,36,4
      COLOUR133
      CLS

      VDU24,100;300;800;700;
      GCOL0,132
      CLG

[RichardRussell]

Is it possible to clear only text area or clear only graphics area?

CLS (VDU 12) and CLG (VDU 16) respectively, or am I misunderstanding?

[Ivan]

Sorry for not writing correct grammar but will text below be understandable:

If I use VDU 12 or VDU 16 or CLS or CLG all the screen area is erased.

I'm only trying to erase text area or graphics area - not both.

REM graphics_window
VDU 24,0,0,1847,1400

REM text_window
VDU 28,0,5,80,0

PRINT TAB(0,0)"CLS test"

MOVE 50,50
DRAW 1200,50

IF condition_what_ever THEN
CLS or VDU 12 REM clear only text window
ELSE
CLG or VDU 16 REM clear only graphics window
ENDIF

[RichardRussell]

If I use VDU 12 or VDU 16 or CLS or CLG all the screen area is erased.

By default, yes, but after you define a text viewport with VDU 28... CLS clears only that area:

Code: Select all

      MODE 8
      VDU 28,0,5,79,0
      COLOUR 128+1
      CLS

and after you define a graphics viewport with VDU 24... CLG clears only that area:

Code: Select all

      MODE 8
      VDU 24,0;0;1278;800;
      GCOL 128+4
      CLG

You need to be careful with the parameters when you set the viewports because if they are out-of-range the command may be ignored.

[Ivan]

I think I'm not clear in my writing. I'm trying to have both types of areas on screen at the same time. I attach a drawing.

text_and_graphics_on_same_screen.jpg

[RichardRussell]

I'm trying to have both types of areas on screen at the same time.

Yes, you were perfectly clear. My first code snippet defines a text viewport occupying the top 6 lines (rows) and the second snippet defines a graphics viewport occupying the bottom 800 graphics units. If you combine the two snippets into one program you get exactly what you describe, thus:

Code: Select all

      MODE 8

      VDU 28,0,5,79,0
      VDU 24,0;0;1278;800;

      COLOUR 128+1
      GCOL 128+4

      CLS
      CLG

This is what it produces (red is the text viewport, blue is the graphics viewport):

viewports.png

[Ivan]

Exactly what I wanted to achieve.

Thanks.