feat: Take screenshots by el · Pull Request #759 · crosspoint-reader/crosspoint-reader

el · 2026-02-08T01:33:10Z

Summary

What is the goal of this PR? Implements a take-screenshot feature
What changes are included?

Quick press Power button and Down button at the same time to take a screenshot
Screenshots are saved in screenshots folder

Additional Context

Currently it does not use the device orientation.

Example screenshots:

screenshot-6771.bmp

screenshot-14158.bmp

AI Usage

Did you use AI tools to help write this code? _** YES

CaptainFrito · 2026-02-08T03:13:28Z

Very cool idea, would it be a good idea to add a visual indication that a screenshot was taken?

el · 2026-02-08T11:41:40Z

Very cool idea, would it be a good idea to add a visual indication that a screenshot was taken?

Done

CaptainFrito · 2026-02-08T12:54:13Z

Hey @el, sorry to nitpick but if you have the setting "Short power button click" set to "sleep", when trying to take screenshots the device goes to sleep if you're not careful to press both buttons exactly at the same time. Not sure that's a big deal, I still managed to take a few screenshots.

lib/GfxRenderer/BitmapHelpers.cpp

lib/FsHelpers/FsHelpers.cpp

ngxson · 2026-02-09T00:51:51Z

lib/FsHelpers/FsHelpers.cpp

+
+  for (int y = 0; y < height; y++) {
+    const uint8_t* fbRow = framebuffer + (height - 1 - y) * fbRowSize;
+    if (file.write(fbRow, fbRowSize) != fbRowSize) {


An extra idea: you can rotate the image on-the-fly by allocating a row of pixels on the stack, then fill it.

The shorter edge of the screen is 480 pixels, with 1bpp that means 60 bytes to be allocated, we should always have enough memory for that.

would you mind if I submit a patch here to rotate the bitmap on-the-fly?

not at all, feel free to update

Eloren1 · 2026-02-09T10:27:09Z

Can you please add Take screenshot button to a quick reader menu as well? (hold ok to open)

bramschulting

Super cool!

bramschulting · 2026-02-09T16:58:55Z

src/main.cpp

+    return;
+  }
+
+  String filename_str = "/screenshots/screenshot-" + String(millis()) + ".bmp";


At some point millis() wraps around. This results in the (incredibly small) chance of the same name being used twice, but more importantly the screenshots will potentially be out of order. Perhaps we can store the last 'screenshot number' as a uint16 in CrossPointState? That would give room for 65,535 screenshots before this becomes a problem.

That would give room for 65,535 screenshots before this becomes a problem.

wrapped screenshot number + millis = infinite amount of screenshots

I would have used date+time but x4 doesnt have an rtc :)

I think this is enough for now

el · 2026-02-09T22:13:01Z

Can you please add Take screenshot button to a quick reader menu as well? (hold ok to open)

I dont see how it would be useful, you mean take a screenshot after closing the menu?

If so, I think we can do that after this is merged.

lib/FsHelpers/FsHelpers.cpp

ngxson · 2026-02-09T22:50:10Z

lib/FsHelpers/FsHelpers.cpp

+
+  for (int y = 0; y < height; y++) {
+    const uint8_t* fbRow = framebuffer + (height - 1 - y) * fbRowSize;
+    if (file.write(fbRow, fbRowSize) != fbRowSize) {


would you mind if I submit a patch here to rotate the bitmap on-the-fly?

Eloren1 · 2026-02-09T23:38:08Z

Can you please add Take screenshot button to a quick reader menu as well? (hold ok to open)

I dont see how it would be useful, you mean take a screenshot after closing the menu?

If so, I think we can do that after this is merged.

Yes after closing. So it is possible to do one handed. And more noticeable

lib/FsHelpers/FsHelpers.cpp

ngxson

I added the 90d ccw rotation in the last commit, should work fine now.

I think fixed rotation should already be enough for now, as most the time we use the default portrait orientation.

One thing to note: it would be nice if we can download the image from web UI. Currently I need to take out the SD card to get the image.

osteotek · 2026-02-13T11:11:12Z

I’ve been testing this and found that setting the “Short power button click” to “sleep” actually conflicts with the combination for taking screenshots. And overall, I believe the current input manager isn’t very well-suited for reading multiple key combinations at once. Perhaps it would be better to add an action for taking screenshots to the reader menu?

el · 2026-02-13T12:29:43Z

I’ve been testing this and found that setting the “Short power button click” to “sleep” actually conflicts with the combination for taking screenshots. And overall, I believe the current input manager isn’t very well-suited for reading multiple key combinations at once. Perhaps it would be better to add an action for taking screenshots to the reader menu?

@Eloren1 has also suggested that change. I have implemented the Take Screenshot to the menu and also moved all logic to a new util.

I have also increased sleep duration slightly to avoid conflicts.

osteotek · 2026-02-13T12:35:38Z

Thank you for the changes! I guess my question is, do we really need button combination for taking screenshots? Now that we have menu option, I am not sure it is that much required, considering we have to change existing logic to properly support it. @crosspoint-reader/firmware-maintainers what do you think

el · 2026-02-13T12:40:14Z

Thank you for the changes! I guess my question is, do we really need button combination for taking screenshots? Now that we have menu option, I am not sure it is that much required, considering we have to change existing logic to properly support it. @crosspoint-reader/firmware-maintainers what do you think

I think it is still usefull, I imagine this feature could be used when

You want to share your home screen or recents
Someone creates a PR that affects the UI, they can share its screenshot.

osteotek · 2026-02-13T12:44:07Z

Thank you for the changes! I guess my question is, do we really need button combination for taking screenshots? Now that we have menu option, I am not sure it is that much required, considering we have to change existing logic to properly support it. @crosspoint-reader/firmware-maintainers what do you think

I think it is still usefull, I imagine this feature could be used when

You want to share your home screen or recents

Someone creates a PR that affects the UI, they can share its screenshot.

Absolutely, I am not talking about screenshot feature in general, it is useful, thank you for this btw. I'm just not sure if I like button overloading. But let's wait for other maintainers opinion

ngxson · 2026-02-18T23:26:47Z

Personally I think it's still be useful for development and bug reports in general. The implementation introduced in this PR is easy enough, so I think it's worth merging into master.

Re. problem with key combination, one idea is to add a new dialog that will be shown when holding power button, and we can move the "screenshot" to that dialog menu. Quite the same idea as on android (see screenshot below). Probably worth discussing this as an UI feature.

coderabbitai · 2026-02-19T20:37:22Z

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📝 Walkthrough

Walkthrough

Adds a screenshot feature: hotkey (Power + Volume Down) and reader-menu trigger capture the framebuffer, save a rotated 1-bit BMP to /screenshots/, and show a brief on-screen confirmation. Also adds BMP header utilities and translations for the new menu label.

Changes

Cohort / File(s)	Summary
Screenshot utility `src/util/ScreenshotUtil.h`, `src/util/ScreenshotUtil.cpp`	New ScreenshotUtil with `takeScreenshot()` and `saveFramebufferAsBmp()` — captures framebuffer, rotates 90° CCW, writes 1-bit BMP to `/screenshots/screenshot-<ms>.bmp`, handles directory/file I/O, errors, and draws a brief border confirmation.
Reader integration `src/activities/reader/EpubReaderActivity.h`, `src/activities/reader/EpubReaderActivity.cpp`, `src/activities/reader/EpubReaderMenuActivity.h`	Adds `MenuAction::SCREENSHOT`, inserts menu item, adds `pendingScreenshot` flag and deferred-capture flow guarded by render mutex; menu confirm triggers screenshot after next render completes.
Input loop & settings `src/main.cpp`, `src/CrossPointSettings.h`	Detects Power+VolumeDown combo in main loop with debounce and guard against auto-sleep; calls ScreenshotUtil. Adjusts power-button duration return value for SLEEP branch.
BMP support `lib/GfxRenderer/Bitmap.h`, `lib/GfxRenderer/BitmapHelpers.h`, `lib/GfxRenderer/BitmapHelpers.cpp`	Adds packed `BmpHeader` (file/info headers), `RgbQuad` and `colors[]`, extends `BmpReaderError` with multiple cases, and new `createBmpHeader()` to initialize 1-bit BMP headers/colour table and sizes.
I18n / Translations `lib/I18n/I18nKeys.h`, `lib/I18n/translations/english.yaml`, `.../czech.yaml`, `.../french.yaml`, `.../german.yaml`, `.../portuguese.yaml`, `.../russian.yaml`, `.../spanish.yaml`, `.../swedish.yaml`	Adds new string id `STR_SCREENSHOT_BUTTON` and provides translations in eight languages.
Docs `USER_GUIDE.md`	Documents screenshot methods: Power+VolumeDown hotkey and reader-menu "Take screenshot" (via Confirm in reader menu).

Sequence Diagram(s)

sequenceDiagram
    actor User
    participant Main as main.cpp
    participant ScreenshotUtil as ScreenshotUtil
    participant Gfx as GfxRenderer
    participant Storage as Storage

    User->>Main: Press Power + Volume Down
    Main->>ScreenshotUtil: takeScreenshot(renderer)
    ScreenshotUtil->>Gfx: request framebuffer
    Gfx-->>ScreenshotUtil: framebuffer bits
    ScreenshotUtil->>Storage: ensure /screenshots/ exists
    ScreenshotUtil->>ScreenshotUtil: rotate 90° CCW & build BMP header
    ScreenshotUtil->>Storage: write BMP header + pixel data
    ScreenshotUtil->>Gfx: draw temporary border confirmation
    Storage-->>ScreenshotUtil: write success/failure
    ScreenshotUtil-->>Main: return result

sequenceDiagram
    actor User
    participant Menu as EpubReaderMenuActivity
    participant Reader as EpubReaderActivity
    participant Renderer as GfxRenderer
    participant ScreenshotUtil as ScreenshotUtil
    participant Storage as Storage

    User->>Menu: Open reader menu & select "Take screenshot"
    Menu->>Reader: MenuAction::SCREENSHOT
    Reader->>Reader: set pendingScreenshot
    Reader->>Renderer: complete current render (holds render mutex)
    Reader->>Reader: detect pendingScreenshot, clear flag
    Reader->>ScreenshotUtil: takeScreenshot(renderer)
    ScreenshotUtil->>Renderer: get framebuffer
    ScreenshotUtil->>Storage: save BMP
    ScreenshotUtil->>Renderer: show confirmation border

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'feat: Take screenshots' clearly and concisely summarizes the main feature addition—screenshot functionality—which is the primary goal of the entire changeset.
Description check	✅ Passed	The description is directly related to the changeset, explaining the goal (implementing screenshot feature), the trigger mechanism (Power + Down buttons), storage location (screenshots folder), and noting it's a work-in-progress regarding device orientation.

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osteotek · 2026-02-20T13:41:52Z

@el if I press screenshot combination while page is still rendering I get crash with this error. Might be related to issue Copilot suggested

assert failed: xQueueGenericSend queue.c:832 (pxQueue->pcHead != ((void *)0) || pxQueue->u.xSemaphore.xMutexHolder == ((void *)0) || pxQueue->u.xSemaphore.xMutexHolder == xTaskGetCurrentTaskHandle())

Co-authored-by: Copilot <[email protected]>

src/main.cpp

src/activities/reader/EpubReaderActivity.cpp

src/main.cpp

src/CrossPointSettings.h

USER_GUIDE.md

el · 2026-02-20T20:42:20Z

@daveallie fyi

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ngxson requested a review from a team February 11, 2026 17:35

el dismissed ngxson’s stale review via 6450ce7 February 13, 2026 11:51

osteotek mentioned this pull request Feb 18, 2026

Feature: Screenshots #976

Open

el closed this Feb 19, 2026

el force-pushed the screenshot branch from f0c2e64 to d461d93 Compare February 19, 2026 20:41

Eliz Kilic added 7 commits February 19, 2026 21:12

take screenshot

6307545

revert

e2c362d

create bmp

6776366

update

6268c5a

refactor creator

0cf31ef

fix imports

0f5c18c

format files

9912987

el and others added 2 commits February 20, 2026 13:42

Update src/util/ScreenshotUtil.cpp

89cf2b1

Co-authored-by: Copilot <[email protected]>

Update src/main.cpp

ccd70f2

Co-authored-by: Copilot <[email protected]>

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Eliz Kilic added 3 commits February 20, 2026 13:54

revert change

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add render lock

b43ae9f

fix

03dcd9e

el requested a review from ngxson February 20, 2026 15:14

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Update src/CrossPointSettings.h

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osteotek dismissed ngxson’s stale review via cb30fd2 February 20, 2026 18:15

Update USER_GUIDE.md

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osteotek approved these changes Feb 20, 2026

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osteotek requested a review from ngxson February 20, 2026 18:16

daveallie approved these changes Feb 22, 2026

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daveallie merged commit c1fad16 into crosspoint-reader:master Feb 22, 2026
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Summary

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AI Usage

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Walkthrough

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