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  • Contrast 0 rendering;

    Can you make it possible to render to the Video memory when the screen is off (contrast 0) or is the video memory inaccessible? I use the contrast to do full screen fades and it would be advantageous to be able to pre render a complex back pane with out the user seeing the build process.

  • #2


    You can probably do this atm with the uVGA module, but most likely not with the rest as contrast 0 'turns off' the display.

    Which display are you using? There maybe and 'easy' way of achieving what you want.
    Mark

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    • #3


      I was using a uOLED 32028 P1 - GFX2 but I now use uLCD 28T_GFX2 and the contrast issue has gone away as there IS no contrast control . There is a nasty white screen at boot time though, now do I stop this?

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      • #4


        No, most LCD screens do not have contrast control.



        Since LCDs have backlights and OLEDs don't you can often see a 'white screen' during startup.



        Which module do you want some 'screen off but updatable' code for?
        Mark

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        • #5


          ESPsupport wrote:
          No, most LCD screens do not have contrast control.



          Since LCDs have backlights and OLEDs don't you can often see a 'white screen' during startup.



          Which module do you want some 'screen off but updatable' code for?
          The uLCD-28PT_GFX2 Please. Is it possible to gain control of the back light in software or can you clear the video memory to black prior to turning the back light on in the PmmC code?

          Rendering images partially off screen seems to cause weird wrapping issues of the graphic image. It's like it's not being clipped properly any more. Is this a known issue?

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          • #6


            On your display you can turn the backlight on and off using



            pin_HI(BACKLITE) ;



            and



            pin_LO(BACKLITE) ;



            This will give you the ability to appear to update the screen whilst it is not visible (well in most lighting conditions anyway)



            If you want/need to render images partially off the screen you should use gfx_Clipping(ON). You may also need gfx_ClipWindow(x,x,x,x), depending on what else you are doing.



            There were some bugs with clipping in early PmmCs but all recent PmmCs have been ok.
            Mark

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            • #7


              I've tried turning the screen off as the first line of main() but you must turn the screen on in your set up code prior to me turning it back off as there is still a nasty white full screen flash.
              Any chance of some Pmmc code that doesn't turn it on as it looks a bit untidy?

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              • #8


                Any chance of a pmmc without the nasty white flash (something a bit more becoming of the various performance car dash clocks it will be replacing) ?

                Lyndon.

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                • #9


                  Sorry, we are obliged to initialize the displays using the LCD (or OLED) panel manufacturer's recommended initialization techniques in order to prevent/avoid/you name it damage to the physical panel due to 'incorrect' initialization.



                  For some panels this results in a 'neat' initialization, for others it results in a flash, for some even more than one flash.



                  Of course, there maybe something we could do differently, but it's not a quick solution, so please bear with us whilst we investigate.
                  Mark

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                  • #10


                    I don't mind taking one for the team to find out if this would actually cause a problem. I can't see how having the back light turned off during initialisation would causing any issues.

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