Display Offset

[tim]

Can anyone assist how in how i might offset the display up or down to enable characters to appear nearer the top or bottom of the display. I’m not trying to enlarge area W 136 H 96 just trying shift it vertically. Many thanks Tim

[Michael]

Try adjusting these values in spec/video_properties.h:

#define _NTSC_LINE_STOP_VSYNC 3
#define _NTSC_LINE_DISPLAY 216

[tim]

Hi,

Im in fact PAL so I tried I tried changing #define _PAL_LINE_DISPLAY 280 and I could get characters towards the bottom of the screen but they were double size and flashing a bit.

I noticed in TVout.cpp there is a
/* shift the pixel buffer in any direction
* This function will shift the screen in a direction by any distance.
*
* Arguments:
* distance:
* The distance to shift the screen
* direction:
* The direction to shift the screen the direction and the integer values:
* UP =0
* DOWN =1
* LEFT =2
* RIGHT =3

I tried this but it appears not to work with video experimenter?

[Michael]

The pixel shifting is about moving pixels within the buffer, not moving the buffer’s position on the screen. All these functions should work with the Video Experimenter (because that’s normal TVout capability).

Why do you want to move the position of the overlay buffer? Is it not in the right place?

[tim]

Thanks Michael

l sorry I thought “shift” was to move the buffer in the video frame as it says “The distance to shift the screen” “This function will shift the screen in a direction by any distance” etc.

Ive enclosed a picture to show you what i mean – bascially i have some data to overlay on the screen but i want to move it
right down to the very bottom on the screen so as not to get in the way of the picture too much. This is about as low as I can get the
characters to display properly.

Have you any other ideas?

Thanks Tim

[Author]

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