[U-Boot] lcd-console / display rotation

[U-Boot] lcd-console / display rotation

[Hannes Petermaier]

Hello everybody,

A short question about lcd-console:

Today u-boot only supports a 'linear framebuffer', meaning the next pixel 
of a character is allways right after left and the framebuffer address is 
incrementing.
We call this the display is mounted with 0? rotation.

In some cases we have a rotated display.
Maybe rotated by 90? to have portrait mode or even 180? due to mechanical 
issues.

My question is:
Is anybody currently working around this, having rotated display ?
If not so, i would like start a implementation.

180? is quite easy, we only need to add some offset (total len of 
framebuffer) to our framebuffer base address and do -- instead ++ for 
drawing characters. Font can be reused.

In the other cases, 90? and 270? it will maybe a bit tricky. I think a 
?rotated font? is also necessary.

Of course we have to think about the other functions like scroll up/down.

best regards,
hannes

[U-Boot] lcd-console / display rotation

[Simon Glass]

+Anatolij, Nikita

Hi,

On 2 March 2015 at 03:12, Hannes Petermaier
<Hannes.Petermaier@br-automation.com> wrote:
> Hello everybody,
>
> A short question about lcd-console:
>
> Today u-boot only supports a 'linear framebuffer', meaning the next pixel
> of a character is allways right after left and the framebuffer address is
> incrementing.
> We call this the display is mounted with 0? rotation.
>
> In some cases we have a rotated display.
> Maybe rotated by 90? to have portrait mode or even 180? due to mechanical
> issues.
>
> My question is:
> Is anybody currently working around this, having rotated display ?
> If not so, i would like start a implementation.
>
> 180? is quite easy, we only need to add some offset (total len of
> framebuffer) to our framebuffer base address and do -- instead ++ for
> drawing characters. Font can be reused.
>
> In the other cases, 90? and 270? it will maybe a bit tricky. I think a
> ?rotated font? is also necessary.
>
> Of course we have to think about the other functions like scroll up/down.

I don't know of anything, but it sounds useful.

Also I wonder if some hardware has support for this?

Nikita (on CC) is tidying up this part of U-Boot so get in touch with him.

Regards,
Simon

[U-Boot] lcd-console / display rotation

[Hannes Petermaier]

> 
> +Anatolij, Nikita
> 
> Hi,
Hi,
many thanks for response.

> 
> On 2 March 2015 at 03:12, Hannes Petermaier
> <Hannes.Petermaier@br-automation.com> wrote:
> > Hello everybody,
> >
> > A short question about lcd-console:
> >
> > Today u-boot only supports a 'linear framebuffer', meaning the next 
pixel
> > of a character is allways right after left and the framebuffer address 
is
> > incrementing.
> > We call this the display is mounted with 0? rotation.
> >
> > In some cases we have a rotated display.
> > Maybe rotated by 90? to have portrait mode or even 180? due to 
mechanical
> > issues.
> >
> > My question is:
> > Is anybody currently working around this, having rotated display ?
> > If not so, i would like start a implementation.
> >
> > 180? is quite easy, we only need to add some offset (total len of
> > framebuffer) to our framebuffer base address and do -- instead ++ for
> > drawing characters. Font can be reused.
> >
> > In the other cases, 90? and 270? it will maybe a bit tricky. I think a
> > ?rotated font? is also necessary.
> >
> > Of course we have to think about the other functions like scroll 
up/down.
> 
> I don't know of anything, but it sounds useful.
Okay, Anatolij doesn't also know anything that there is something going 
on.
I will start to form some ideas how to implement such feature.

> 
> Also I wonder if some hardware has support for this?
"Support" is the wrong word, sometimes the the lcd is mechanical built in 
rotated and the logical start of the framebuffer isn't as usual at 
top-left, rather it it bottom-right - means rotated by 180?.
> 
> Nikita (on CC) is tidying up this part of U-Boot so get in touch with 
him.
Nikita, whats your opinion around that ?

> Regards,
> Simon
best regards,
Hannes

[U-Boot] lcd-console / display rotation

[Nikita Kiryanov]

Hi Hannes,

On 03/03/2015 12:31 PM, Hannes Petermaier wrote:
>>
>> +Anatolij, Nikita
>>
>> Hi,
> Hi,
> many thanks for response.
>
>>
>> On 2 March 2015 at 03:12, Hannes Petermaier
>> <Hannes.Petermaier@br-automation.com> wrote:
>>> Hello everybody,
>>>
>>> A short question about lcd-console:
>>>
>>> Today u-boot only supports a 'linear framebuffer', meaning the next
> pixel
>>> of a character is allways right after left and the framebuffer address
> is
>>> incrementing.
>>> We call this the display is mounted with 0? rotation.
>>>
>>> In some cases we have a rotated display.
>>> Maybe rotated by 90? to have portrait mode or even 180? due to
> mechanical
>>> issues.
>>>
>>> My question is:
>>> Is anybody currently working around this, having rotated display ?
>>> If not so, i would like start a implementation.
>>>
>>> 180? is quite easy, we only need to add some offset (total len of
>>> framebuffer) to our framebuffer base address and do -- instead ++ for
>>> drawing characters. Font can be reused.
>>>
>>> In the other cases, 90? and 270? it will maybe a bit tricky. I think a
>>> ?rotated font? is also necessary.
>>>
>>> Of course we have to think about the other functions like scroll
> up/down.
>>
>> I don't know of anything, but it sounds useful.
> Okay, Anatolij doesn't also know anything that there is something going
> on.
> I will start to form some ideas how to implement such feature.
>
>>
>> Also I wonder if some hardware has support for this?
> "Support" is the wrong word, sometimes the the lcd is mechanical built in
> rotated and the logical start of the framebuffer isn't as usual at
> top-left, rather it it bottom-right - means rotated by 180?.
>>
>> Nikita (on CC) is tidying up this part of U-Boot so get in touch with
> him.
> Nikita, whats your opinion around that ?

Sounds like a useful feature. I do not anticipate much changes to lcd_console.c
in the near future (not until I try to merge video console with the lcd console
anyway), so for now you can work with it fairly uninterrupted. I only ask that
you avoid adding platform specific code to it. The only platform specific thing
in there right now is a mention of panel_info, and that should disappear soon
as well (replaced with a function call).

-- 
Regards,
Nikita Kiryanov

[U-Boot] lcd-console / display rotation

[Anatolij Gustschin]

Hi,

On Mon, 2 Mar 2015 11:12:23 +0100
Hannes Petermaier <Hannes.Petermaier@br-automation.com> wrote:

> Hello everybody,
> 
> A short question about lcd-console:
> 
> Today u-boot only supports a 'linear framebuffer', meaning the next pixel 
> of a character is allways right after left and the framebuffer address is 
> incrementing.
> We call this the display is mounted with 0? rotation.
> 
> In some cases we have a rotated display.
> Maybe rotated by 90? to have portrait mode or even 180? due to mechanical 
> issues.
> 
> My question is:
> Is anybody currently working around this, having rotated display ?

not that I am aware of.

Best regards,

Anatolij