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khmann · 07-16-2011, 11:25 PM

@seaniko7- Pimp : ) How are you using the UI to launch it?

overview, why screen flash is there in the first place:
https://www.mobileread.com/forums/sho...d.php?t=102811 has a nice discussion and mentions many of the design issues with eInk. All updates to the display are relative. Basically in eInk the only way to set the entire page to a uniformly "white" is to turn the entire thing black at once, and then clear it back to white. Because changing any pixel has a pretty strong effect on it's neighbors, modulated by relative amount of the change, and is compounded by each operation. So you lose track of the actual "displayed" value pretty quick.

What this hack is doing is using an undocumented (probably that's why no eBook maker is using it) eInk display mode to force anything over 50% to pure black and the rest to pure white. Note that it is broadstreet (or whoever) themselves that is disabling the screen flash-update in this mode, so probably it was intended for the very way we are using it (though perhaps not in a bash script : ) Since we are "splitting the difference" and going to white AND black at the same time before filling in the details, the display does a reasonable job of assembling the final image.

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Some tweaks could be made, perhaps store the default contrast (though I actually prefer it being forced to 3), and a better way to monitor when the image refresh actually occurs, but regardless

seaniko7 posted test.zip totally works... rock on!

Did I invent this? How about the name "reflash" to describe the effect as opposed to the standard flash.

07-16-2011, 11:25 PM	#12
khmann Enthusiast Posts: 43 Karma: 1658 Join Date: Jul 2011 Device: b006	reflash @seaniko7- Pimp : ) How are you using the UI to launch it? overview, why screen flash is there in the first place: https://www.mobileread.com/forums/sho...d.php?t=102811 has a nice discussion and mentions many of the design issues with eInk. All updates to the display are relative. Basically in eInk the only way to set the entire page to a uniformly "white" is to turn the entire thing black at once, and then clear it back to white. Because changing any pixel has a pretty strong effect on it's neighbors, modulated by relative amount of the change, and is compounded by each operation. So you lose track of the actual "displayed" value pretty quick. What this hack is doing is using an undocumented (probably that's why no eBook maker is using it) eInk display mode to force anything over 50% to pure black and the rest to pure white. Note that it is broadstreet (or whoever) themselves that is disabling the screen flash-update in this mode, so probably it was intended for the very way we are using it (though perhaps not in a bash script : ) Since we are "splitting the difference" and going to white AND black at the same time before filling in the details, the display does a reasonable job of assembling the final image. --------------------- Some tweaks could be made, perhaps store the default contrast (though I actually prefer it being forced to 3), and a better way to monitor when the image refresh actually occurs, but regardless seaniko7 posted test.zip totally works... rock on! Did I invent this? How about the name "reflash" to describe the effect as opposed to the standard flash. Last edited by khmann; 07-16-2011 at 11:27 PM.