[U-Boot] lcd-console / display rotation
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
+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
+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
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).
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
participants (4)
-
Anatolij Gustschin -
Hannes Petermaier -
Nikita Kiryanov -
Simon Glass