GFX Library print fucnction

[Marcos Tadeo]

Hollo

Im using the GFX example,  want to print string and to clear the screen , i use screen_clear(); function,  this is default function gfx example

this is the loop

can be so fast?

do i need to implement a buffer?

or whats is the problem?

thanks a regards

[Karl Ylvisaker]

Hello,

this is the loop

can be so fast?

Could you clarify what you mean by this?

or whats is the problem?

I am not sure either what is the problem - could you elaborate on the behavior you are observing, and how it is different from what you would have expected?

Best regards,
Karl

[Marcos Tadeo]

Hello

Karl Ylvisaker said:

I am not sure either what is the problem - could you elaborate on the behavior you are observing, and how it is different from what you would have expected?

Yes sure, sorry  

I'm thinking , maybe i have a print screen problem , because is flashing , 

attached a video example, here the lcd print a numbers and do a animation , but its no flashing 

I was analyzing the problem  i have no idea if i need to add a buffer funtion or some configuration in sdk_ config.h or nrf_gfx library

i saw this function 

I moved different values, but I don't see any change.

i want to make a watch also, using nrf_calendar library ,  

i can to show a image, and print string characteres with diferents fonts , but the printting is slow

thanks and regards

my english is not good

[Karl Ylvisaker]

Hello again,

Marcos Tadeo said:

my english is not good

No worries at all - I will ask if anything is unclear! :) 

Marcos Tadeo said:

I'm thinking , maybe i have a print screen problem , because is flashing , 

attached a video example, here the lcd print a numbers and do a animation , but its no flashing 

I see - I thought the video might have exaggerated the stuttering on the refresh.
Have you taken a look at the GFX library documentation concerning LCD frame buffering?
Which guide/tutorial are you following, is it the GFX Library example - and if so, is the changes to the while(1) loop above the only modifications you have made to the example?
What configuration are you using for you SPI?

Marcos Tadeo said:

I moved different values, but I don't see any change.

Could you elaborate on what you mean by this? What values did you change, and where did you expect to see the difference?

Best regards,
Karl

[Marcos Tadeo]

Hello Karl

thank you for you reply

Karl Ylvisaker said:

What configuration are you using for you SPI?

this is my SPI Configuration 

Karl Ylvisaker said:

Have you taken a look at the GFX library documentation concerning LCD frame buffering?

Yes, i saw this post Controlling ST7789 LCD with NRF52 DK

the print font is better but i need to implement screen clear like a rect fill

Karl Ylvisaker said:

Which guide/tutorial are you following, is it the GFX Library example - and if so, is the changes to the while(1) loop above the only modifications you have made to the example?

Yes I am using the GFX library example, I changed the SPI Freq 100k to 8M and I implemented Controlling ST7789 LCD with NRF52 DK this example to ST7735 and improved the print method , 

and new screen clear method, 

this is the result

the video shows  this 

i would like to get faster print image

thank and regards 

Tadeo

[Karl Ylvisaker]

Hello again, Tadeo

I am glad to hear that you have made improvements to the screen control! :) 

Marcos Tadeo said:

i would like to get faster print image

Is the primary issue to clear the screen faster (i.e without the gradual overwrite of the screen), or is there a specific 'refresh rate' you are looking for?
In case of the former, do you know that the screen supports this?
In case of the latter, how do you measure this?

Do you have the datasheet for the screen driver?
Does the datasheet of the screen driver mention a recommended way to print the screen, or what you can do to increase the speed of the print?

Best regards,
Karl

[Marcos Tadeo]

Hello karl

thanks for you reply 

I could print fast the image and text . i saw other example  with nrf51

st7735 with nrf51 this link is for image print

Controlling ST7789 LCD with NRF52 DK this post to text fast 

I adapted it into my code, it works 

thank you for you support 

[Karl Ylvisaker]

Thank you for sharing the solution you found - I am happy to read that you've now got it working as you had intended! :) 

Please do not hesitate to open another ticket if you should encounter any issues or questions in the future.

Good luck with your development!

Best regards,
Karl