Add Support for Bitmap-Output

[DerPicknicker]

Hi,

it would be great if the docker container supports .bmp Files as an output. This would help to use cheap esp32 devices. Because the popular libraries doesn't support jpg the conversion is memory intensive and the esp32 is not powerful enough to handle that.

I did a small research and your used library for creating the jpg files is also capable to create the bmp.

Would be a nice addition for this project.

[sibbl]

Hey,

could you please provide which libraries and devices the output should be compatible for? If there are more details on which bmp requirements to follow it shouldn't be that much work to add this.

Thanks in advance!

[DerPicknicker]

Hey @sibbl ,

thank you for the fast response. The main goal would be that I can use this great docker container to send images to ESP32 devices.

See this library : https://github.com/ZinggJM/GxEPD2/tree/master

It supports drawing from HTTP(S) but the file must be encoded as an Bitmap. Because the esp32 is limited by its ram so you can't store both / convert it locally.

Here is an example: https://github.com/ZinggJM/GxEPD2/blob/master/examples/GxEPD2_WiFi_Example/GxEPD2_WiFi_Example.ino

[CptWindows]

Hi, I would also be interested in a Bitmap output, as you can easily display it on an E-INK display using the library linked by @DerPicknicker .
By the way, it looks like ImageMagick supports a BMP output, which would probably make the whole thing easier to implement?

[macmacs]

My minimal fixes add the possibility to get a bmp file.
I use it for exactly this usecase.

[sibbl]

Thanks for the PR, @macmacs! I've just merged it and the new image is building.

[macmacs]

Great :)

[DerPicknicker]

@macmacs on which hardware are you displaying the websites?

[macmacs]

@DerPicknicker I am using this 7.5'' HD epaper with an ESP32 driver.
I adapted the mentioned example.
Works pretty well.

[DerPicknicker]

@macmacs thank you for adding bitmap support. Maybe I will resume now my project. Those eink displays are still too expensive (at bigger sizes).