## Summary
**What is the goal of this PR?**
This change fixes an issue I noticed while reading where occasionally,
especially in italics, some words would have too much space between
them. The problem was that word width calculations were including any
negative X overhang, and combined with a space before the word, that can
lead to an inconsistently large space.
## Additional Context
Screenshots of some problematic text:
| In CrossPoint 1.0 | With this change |
| -- | -- |
| <img
src="https://github.com/user-attachments/assets/87bf0e4b-341f-4ba9-b3ea-38c13bd26363"
width="400" /> | <img
src="https://github.com/user-attachments/assets/bf11ba20-c297-4ce1-aa07-43477ef86fc2"
width="400" /> |
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**NO**_
## Summary
**What is the goal of this PR?**
Compress reader font bitmaps to reduce flash usage by 30.7%.
**What changes are included?**
- New `EpdFontGroup` struct and extended `EpdFontData` with
`groups`/`groupCount` fields
- `--compress` flag in `fontconvert.py`: groups glyphs (ASCII base group
+ groups of 8) and compresses each with raw DEFLATE
- `FontDecompressor` class with 4-slot LRU cache for on-demand
decompression during rendering
- `GfxRenderer` transparently routes bitmap access through
`getGlyphBitmap()` (compressed or direct flash)
- Uses `uzlib` for decompression with minimal heap overhead.
- 48 reader fonts (Bookerly, NotoSans 12-18pt, OpenDyslexic) regenerated
with compression; 5 UI fonts unchanged
- Round-trip verification script (`verify_compression.py`) runs as part
of font generation
## Additional Context
## Flash & RAM
| | baseline | font-compression | Difference |
|--|--------|-----------------|------------|
| Flash (ELF) | 6,302,476 B (96.2%) | 4,365,022 B (66.6%) | -1,937,454 B
(-30.7%) |
| firmware.bin | 6,468,192 B | 4,531,008 B | -1,937,184 B (-29.9%) |
| RAM | 101,700 B (31.0%) | 103,076 B (31.5%) | +1,376 B (+0.5%) |
## Script-Based Grouping (Cold Cache)
Comparison of uncompressed baseline vs script-based group compression
(4-slot LRU cache, cleared each page). Glyphs are grouped by Unicode
block (ASCII, Latin-1, Latin Extended-A, Combining Marks, Cyrillic,
General Punctuation, etc.) instead of sequential groups of 8.
### Render Time
| | Baseline | Compressed (cold cache) | Difference |
|---|---|---|---|
| **Median** | 414.9 ms | 431.6 ms | +16.7 ms (+4.0%) |
| **Pages** | 37 | 37 | |
### Memory Usage
| | Baseline | Compressed (cold cache) | Difference |
|---|---|---|---|
| **Heap free (median)** | 187.0 KB | 176.3 KB | -10.7 KB |
| **Heap free (min)** | 186.0 KB | 166.5 KB | -19.5 KB |
| **Largest block (median)** | 148.0 KB | 128.0 KB | -20.0 KB |
| **Largest block (min)** | 148.0 KB | 120.0 KB | -28.0 KB |
### Cache Effectiveness
| | Misses/page | Hit rate |
|---|---|---|
| **Compressed (cold cache)** | 2.1 | 99.85% |
------
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**YES**_
Implementation was done by Claude Code (Opus 4.6) based on a plan
developed collaboratively. All generated font headers were verified with
an automated round-trip decompression test. The firmware was compiled
successfully but has not yet been tested on-device.
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
## Summary
**What is the goal of this PR?**
Several methods in GfxRenderer were doing a `count()` followed by `at()`
on the fonts map, effectively doing the same map lookup unnecessarily.
This can be avoided by doing a single `find()` and reusing the iterator.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**NO**_
## Summary
- Add embedded image support to EPUB rendering with JPEG and PNG
decoders
- Implement pixel caching system to cache decoded/dithered images to SD
card for faster re-rendering
- Add 4-level grayscale support for display
## Changes
### New Image Rendering System
- Add `ImageBlock` class to represent an image with its cached path and
display dimensions
- Add `PageImage` class as a new `PageElement` type for images on pages
- Add `ImageToFramebufferDecoder` interface for format-specific image
decoders
- Add `JpegToFramebufferConverter` - JPEG decoder with Bayer dithering
and scaling
- Add `PngToFramebufferConverter` - PNG decoder with Bayer dithering and
scaling
- Add `ImageDecoderFactory` to select appropriate decoder based on file
extension
- Add `getRenderMode()` to GfxRenderer for grayscale render mode queries
### Dithering and Grayscale
- Implement 4x4 Bayer ordered dithering for 4-level grayscale output
- Stateless algorithm works correctly with MCU block decoding
- Handles scaling without artifacts
- Add grayscale render mode support (BW, GRAYSCALE_LSB, GRAYSCALE_MSB)
- Image decoders and cache renderer respect current render mode
- Enables proper 4-level e-ink grayscale when anti-aliasing is enabled
### Pixel Caching
- Cache decoded/dithered images to `.pxc` files on SD card
- Cache format: 2-bit packed pixels (4 pixels per byte) with
width/height header
- On subsequent renders, load directly from cache instead of re-decoding
- Cache renderer supports grayscale render modes for multi-pass
rendering
- Significantly improves page navigation speed for image-heavy EPUBs
### HTML Parser Integration
- Update `ChapterHtmlSlimParser` to process `<img>` tags and extract
images from EPUB
- Resolve relative image paths within EPUB ZIP structure
- Extract images to cache directory before decoding
- Create `PageImage` elements with proper scaling to fit viewport
- Fall back to alt text display if image processing fails
### Build Configuration
- Add `PNG_MAX_BUFFERED_PIXELS=6402` to support up to 800px wide images
### Test Script
- Generate test EPUBs with annotated JPEG and PNG images
- Test cases cover: grayscale (4 levels), centering, scaling, cache
performance
## Test plan
- [x] Open EPUB with JPEG images - verify images display with proper
grayscale
- [x] Open EPUB with PNG images - verify images display correctly and no
crash
- [x] Navigate away from image page and back - verify faster load from
cache
- [x] Verify grayscale tones render correctly (not just black/white
dithering)
- [x] Verify large images are scaled down to fit screen
- [x] Verify images are centered horizontally
- [x] Verify page serialization/deserialization works with images
- [x] Verify images rendered in landscape mode
## Test Results
[png](https://photos.app.goo.gl/5zFUb8xA8db3dPd19)
[jpeg](https://photos.app.goo.gl/SwtwaL2DSQwKybhw7)
---
### AI Usage
Did you use AI tools to help write this code? _**< YES >**_
---------
Co-authored-by: Matthías Páll Gissurarson <mpg@mpg.is>
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* Definition and use of a central LOG function, that can later be
extended or completely be removed (for public use where debugging
information may not be required) to save flash by suppressing the
-DENABLE_SERIAL_LOG like in the slim branch
* **What changes are included?**
## Additional Context
* By using the central logger the usual:
```
#include <HardwareSerial.h>
...
Serial.printf("[%lu] [WCS] Obfuscating/deobfuscating %zu bytes\n", millis(), data.size());
```
would then become
```
#include <Logging.h>
...
LOG_DBG("WCS", "Obfuscating/deobfuscating %zu bytes", data.size());
```
You do have ``LOG_DBG`` for debug messages, ``LOG_ERR`` for error
messages and ``LOG_INF`` for informational messages. Depending on the
verbosity level defined (see below) soe of these message types will be
suppressed/not-compiled.
* The normal compilation (default) will create a firmware.elf file of
42.194.356 bytes, the same code via slim will create 42.024.048 bytes -
170.308 bytes less
* Firmware.bin : 6.469.984 bytes for default, 6.418.672 bytes for slim -
51.312 bytes less
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _NO_
---------
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
## Summary
Continue my changes to introduce the HAL infrastructure from
https://github.com/crosspoint-reader/crosspoint-reader/pull/522
This PR touches quite a lot of files, but most of them are just name
changing. It should not have any impacts to the end behavior.
## Additional Context
My plan is to firstly add this small shim layer, which sounds useless at
first, but then I'll implement an emulated driver which can be helpful
for testing and for development.
Currently, on my fork, I'm using a FS driver that allow "mounting" a
local directory from my computer to the device, much like the `-v` mount
option on docker. This allows me to quickly reset `.crosspoint`
directory if anything goes wrong. I plan to upstream this feature when
this PR get merged.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? NO
## Summary
Ref https://github.com/crosspoint-reader/crosspoint-reader/pull/737
This PR further reduce ~25ms from rendering time, testing inside the
Setting screen:
```
master:
[68440] [GFX] Time = 73 ms from clearScreen to displayBuffer
PR:
[97806] [GFX] Time = 47 ms from clearScreen to displayBuffer
```
And in extreme case (fill the entire screen with black or gray color):
```
master:
[1125] [ ] Test fillRectDither drawn in 327 ms
[1347] [ ] Test fillRect drawn in 222 ms
PR:
[1334] [ ] Test fillRectDither drawn in 225 ms
[1455] [ ] Test fillRect drawn in 121 ms
```
Note that
https://github.com/crosspoint-reader/crosspoint-reader/pull/737 is NOT
applied on top of this PR. But with 2 of them combined, it should reduce
from 47ms --> 42ms
## Details
This PR based on the fact that function calls are costly if the function
is small enough. For example, this simple call:
```
int rotatedX = 0;
int rotatedY = 0;
rotateCoordinates(x, y, &rotatedX, &rotatedY);
```
Generated assembly code:
<img width="771" height="215" alt="image"
src="https://github.com/user-attachments/assets/37991659-3304-41c3-a3b2-fb967da53f82"
/>
This adds ~10 instructions just to prepare the registers prior to the
function call, plus some more instructions for the function's
epilogue/prologue. Inlining it removing all of these:
<img width="1471" height="832" alt="image"
src="https://github.com/user-attachments/assets/b67a22ee-93ba-4017-88ed-c973e28ec914"
/>
Of course, this optimization is not magic. It's only beneficial under 3
conditions:
- The function is small, not in size, but in terms of effective
instructions. For example, the `rotateCoordinates` is simply a jump
table, where each branch is just 3-4 inst
- The function has multiple input arguments, which requires some move to
put it onto the correct place
- The function is called very frequently (i.e. critical path)
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? **NO**
## Summary
This PR optimizes the `fillRectDither` function, making it as fast as a
normal `fillRect`
Testing code:
```cpp
{
auto start_t = millis();
renderer.fillRectDither(0, 0, renderer.getScreenWidth(), renderer.getScreenHeight(), Color::LightGray);
auto elapsed = millis() - start_t;
Serial.printf("[%lu] [ ] Test fillRectDither drawn in %lu ms\n", millis(), elapsed);
}
{
auto start_t = millis();
renderer.fillRect(0, 0, renderer.getScreenWidth(), renderer.getScreenHeight(), true);
auto elapsed = millis() - start_t;
Serial.printf("[%lu] [ ] Test fillRect drawn in %lu ms\n", millis(), elapsed);
}
```
Before:
```
[1125] [ ] Test fillRectDither drawn in 327 ms
[1347] [ ] Test fillRect drawn in 222 ms
```
After:
```
[1065] [ ] Test fillRectDither drawn in 238 ms
[1287] [ ] Test fillRect drawn in 222 ms
```
## Visual validation
Before:
<img width="415" height="216" alt="Screenshot 2026-02-07 at 01 04 19"
src="https://github.com/user-attachments/assets/5802dbba-187b-4d2b-a359-1318d3932d38"
/>
After:
<img width="420" height="191" alt="Screenshot 2026-02-07 at 01 36 30"
src="https://github.com/user-attachments/assets/3c3c8e14-3f3a-4205-be78-6ed771dcddf4"
/>
## Details
The original version is quite slow because it does quite a lot of
computations. A single pixel needs around 20 instructions just to know
if it's black or white:
<img width="1170" height="693" alt="Screenshot 2026-02-07 at 00 15 54"
src="https://github.com/user-attachments/assets/7c5a55e7-0598-4340-8b7b-17307d7921cb"
/>
With the new, templated and more light-weight approach, each pixel takes
only 3-4 instructions, the modulo operator is translated into bitwise
ops:
<img width="1175" height="682" alt="Screenshot 2026-02-07 at 01 47 51"
src="https://github.com/user-attachments/assets/4ec2cf74-6cc0-4b5b-87d5-831563ef164f"
/>
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? **NO**
## Summary
* **What is the goal of this PR?**
The goal of this PR is to deliver a fix for or at least mitigate the
impact of the issue described in #561
* **What changes are included?**
This PR includes a new option "Sunlight Fading Fix" under "Settings ->
Display".
When set to ON, we will disable the displays analog supply voltage after
every update and turn it back on before the next update.
## Additional Context
* Until now, I was only able to do limited testing because of limited
sunlight at my location, but the fix seems to be working. I'll also
attach a pre-built binary based on 0.16.0 (current master) with the fix
applied to the linked ticket, as building this fix is a bit annoying
because the submodule open-x4-sdk also needs an update.
* [PR in
open-x4-sdk](https://github.com/open-x4-epaper/community-sdk/pull/15)
needs to be merged first, we also need to add another commit to this
here PR, updating this dependency.
* I decided to hide this behind a default-OFF option. While I'm not
really concerned that this fix might potentially damage the display,
someone more knowledgeable on E-Ink technology could maybe have a look
at this.
* There's a binary attached in the linked issue, if someone has the
required sunlight to test this in-depth.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**NO**_
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
### What is the goal of this PR?
- Visual UI overhaul
- UI theme selection
### What changes are included?
- Added a setting "UI Theme": Classic, Lyra
- The classic theme is the current Crosspoint theme
- The Lyra theme implements these mockups:
https://www.figma.com/design/UhxoV4DgUnfrDQgMPPTXog/Lyra-Theme?node-id=2003-7596&t=4CSOZqf0n9uQMxDt-0
by Discord users yagofarias, ruby and gan_shu
- New functions in GFXRenderer to render rounded rectangles, greyscale
fills (using dithering) and thick lines
- Basic UI components are factored into BaseTheme methods which can be
overridden by each additional theme. Methods that are not overridden
will fallback to BaseTheme behavior. This means any new
features/components in CrossPoint only need to be developed for the
"Classic" BaseTheme.
- Additional themes can easily be developed by the community using this
foundation
## Additional Context
- Only the Home, Library and main Settings screens have been implemented
so far, this will be extended to the transfer screens and chapter
selection screen later on, but we need to get the ball rolling somehow
:)
- Loading extra covers on the home screen in the Lyra theme takes a
little more time (about 2 seconds), I added a loading bar popup (reusing
the Indexing progress bar from the reader view, factored into a neat UI
component) but the popup adds ~400ms to the loading time.
- ~~Home screen thumbnails will need to be generated separately for each
theme, because they are displayed in different sizes. Because we're
using dithering, displaying a thumb with the wrong size causes the
picture to look janky or dark as it does on the screenshots above. No
worries this will be fixed in a future PR.~~ Thumbs are now generated
with a size parameter
- UI Icons will need to be implemented in a future PR.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**PARTIALLY**_
This is not a vibe coded PR. Copilot was used for autocompletion to save
time but I reviewed, understood and edited all generated code.
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* **What is the goal of this PR?**
- Adds basic CSS parsing to EPUBs and determine the CSS rules when
rendering to the screen so that text is styled correctly. Currently
supports bold, underline, italics, margin, padding, and text alignment
## Additional Context
- My main reason for wanting this is that the book I'm currently
reading, Carl's Doomsday Scenario (2nd in the Dungeon Crawler Carl
series), relies _a lot_ on styled text for telling parts of the story.
When text is bolded, it's supposed to be a message that's rendered
"on-screen" in the story. When characters are "chatting" with each
other, the text is bolded and their names are underlined. Plus, normal
emphasis is provided with italicizing words here and there. So, this
greatly improves my experience reading this book on the Xteink, and I
figured it was useful enough for others too.
- For transparency: I'm a software engineer, but I'm mostly frontend and
TypeScript/JavaScript. It's been _years_ since I did any C/C++, so I
would not be surprised if I'm doing something dumb along the way in this
code. Please don't hesitate to ask for changes if something looks off. I
heavily relied on Claude Code for help, and I had a lot of inspiration
from how [microreader](https://github.com/CidVonHighwind/microreader)
achieves their CSS parsing and styling. I did give this as good of a
code review as I could and went through everything, and _it works on my
machine_ 😄
### Before
### After
---
### AI Usage
Did you use AI tools to help write this code? **YES**, Claude Code
## Summary
* Truncating chapter titles using utf8 safe functions (Cyrillic titles
were split mid codepoint)
* refactoring of lib/Utf8
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? _**< PARTIALLY >**_
## Summary
* refactors Indexing popups into ScreenComponents (they had different
implementations in different files)
* removes Indexing popup for small chapters
* only show Indexing popup (without progress bar) for large chapters
(using same minimum file size condition as for progress bar before)
## Additional Context
* Having to show even single popup message and redraw the screen slows
down the flow significantly
* Testing results:
* Opening large chapter with progress bar - 11 seconds
* Same chapter without progress bar, only single Indexing popup - 5
seconds
---
### AI Usage
Did you use AI tools to help write this code? _**< PARTIALLY>**_
## Summary
Extracted some changes from
https://github.com/crosspoint-reader/crosspoint-reader/pull/500 to make
reviewing easier
This PR adds HAL (Hardware Abstraction Layer) for display and GPIO
components, making it easier to write a stub or an emulated
implementation of the hardware.
SD card HAL will be added via another PR, because it's a bit more
tricky.
---
### AI Usage
While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.
Did you use AI tools to help write this code? **NO**
## Summary
This was originally a comment in #499, but I'm making it its own PR,
because it doesn't depend on anything there and then I can base that PR
on this one.
Currently, `drawBitmap` is used for covers and sleep wallpaper, and
`drawImage` is used for the boot logo. `drawBitmap` goes row by row and
pixel by pixel, so it respects the renderer orientation. `drawImage`
just calls the `EInkDisplay`'s `drawImage`, which works in the eink
panel's native display orientation.
`drawImage` rotates the x,y coordinates where it's going to draw the
image, but doesn't account for the fact that the northwest corner in
portrait orientation becomes, the southwest corner of the image
rectangle in the native orientation. The boot and sleep activities
currently work around this by calculating the north*east* corner of
where the image should go, which becomes the northwest corner after
`rotateCoordinates`.
I think this wasn't really apparent because the CrossPoint logo is
rotationally symmetrical. The `EInkDisplay` `drawImage` always draws the
image in native orientation, but that looks the same for the "X" image.
If we rotate the origin coordinate in `GfxRenderer`'s `drawImage`, we
can use a much clearer northwest corner coordinate in the boot and sleep
activities. (And then, in #499, we can actually rotate the boot screen
to the user's preferred orientation).
This does *not* yet rotate the actual bits in the image; it's still
displayed in native orientation. This doesn't affect the
rotationally-symmetric logo, but if it's ever changed, we will probably
want to allocate a new `u8int[]` and transpose rows and columns if
necessary.
## Additional Context
I've created an additional branch on top of this to demonstrate by
replacing the logo with a non-rotationally-symmetrical image:
<img width="128" height="128" alt="Cat-in-a-pan-128-bw"
src="https://github.com/user-attachments/assets/d0b239bc-fe75-4ec8-bc02-9cf9436ca65f"
/>
https://github.com/crosspoint-reader/crosspoint-reader/compare/master...maeveynot:rotated-cat
(many thanks to https://notisrac.github.io/FileToCArray/)
As you can see, it is always drawn in native orientation, which makes it
sideways (turned clockwise) in portrait.
---
### AI Usage
No
Co-authored-by: Maeve Andrews <maeve@git.mail.maeveandrews.com>
The current behavior of rendering `?` for an unknown Unicode character
can be hard to distinguish from a typo. Use the standard Unicode
"replacement character" instead, that's what it's designed for:
https://en.wikipedia.org/wiki/Specials_(Unicode_block)
I'm making this PR as a draft because I'm not sure I did everything that
was needed to change the character set covered by the fonts. Running
that script is in its own commit. If this is proper, I'll rebase/squash
into one commit and un-draft.
Co-authored-by: Maeve Andrews <maeve@git.mail.maeveandrews.com>
~~Quick~~ fix for
https://github.com/daveallie/crosspoint-reader/issues/362
(this just applies to the chapter selection menu:)
~~If the orientation is portrait, hints as we know them make sense to
draw. If the orientation is inverted, we'd have to change the order of
the labels (along with everything's position), and if it's one of the
landscape choices, we'd have to render the text and buttons vertically.
All those other cases will be more complicated.~~
~~Punt on this for now by only rendering if portrait.~~
Update: this now draws the hints at the physical button position no
matter what the orientation is, by temporarily changing orientation to
portrait.
---------
Co-authored-by: Maeve Andrews <maeve@git.mail.maeveandrews.com>
## Summary
* **What is the goal of this PR?** (e.g., Fixes a bug in the user
authentication module,
Display the book cover image in the **"Continue Reading"** card on the
home screen, with fast navigation using framebuffer caching.
* **What changes are included?**
- Display book cover image in the "Continue Reading" card on home screen
- Load cover from cached BMP (same as sleep screen cover)
- Add framebuffer store/restore functions (`copyStoredBwBuffer`,
`freeStoredBwBuffer`) for fast navigation after initial render
- Fix `drawBitmap` scaling bug: apply scale to offset only, not to base
coordinates
- Add white text boxes behind title/author/continue reading label for
readability on cover
- Support both EPUB and XTC file cover images
- Increase HomeActivity task stack size from 2048 to 4096 for cover
image rendering
## Additional Context
* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks, specific areas to
focus on).
- Performance: First render loads cover from SD card (~800ms),
subsequent navigation uses cached framebuffer (~instant)
- Memory: Framebuffer cache uses ~48KB (6 chunks × 8KB) while on home
screen, freed on exit
- Fallback: If cover image is not available, falls back to standard
text-only display
- The `drawBitmap` fix corrects a bug where screenY = (y + offset) scale
was incorrectly scaling the base coordinates. Now correctly uses screenY
= y + (offset scale)
1. Refactor Bitmap.cpp/h to expose the options for FloydSteinberg and
brightness/gamma correction at runtime
2. Fine-tune the thresholds for Floyd Steiberg and simple quantization
to better match the display's colors
Turns out that 2 is enough to make the images render properly, so the
brightness boost and gamma adjustment doesn't seem necessary currently
(at least for my test image).
Added a setting to select `fit` or `crop` for cover image on sleep
screen.
Might add a `expand` feature in the future that does not crop but rather
fills the blank space with a mirror of the image.
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
This adds the correctly styled button hints to the keyboard screen as
well as the ability to add hints to the side buttons (and up/down hints
to that screen)
## Additional Context
N/A
## Summary
* Update EpdFontFamily::Style to be u8 instead of u32 (saving 3 bytes
per word)
* Update layout width/height to be u16 from int
* Update page element count to be u16 from u32
* Update text block element count to be u16 from u32
* Bumped section bin version to version 8
## Summary
* Swap to updated SDCardManager which uses SdFat
* Add exFAT support
* Swap to using FsFile everywhere
* Use newly exposed `SdMan` macro to get to static instance of
SDCardManager
* Move a bunch of FsHelpers up to SDCardManager
## Summary
* **What is the goal of this PR?**
Add support for XTC (XTeink X4 native) ebook format, which contains
pre-rendered 480x800 1-bit bitmap pages optimized for e-ink displays.
* **What changes are included?**
- New `lib/Xtc/` library with XtcParser for reading XTC files
- XtcReaderActivity for displaying XTC pages on e-ink display
- XTC file detection in FileSelectionActivity
- Cover BMP generation from first XTC page
- Correct XTG page header structure (22 bytes) and bit polarity handling
## Additional Context
- XTC files contain pre-rendered bitmap pages with embedded status bar
(page numbers, progress %)
- XTG page header: 22 bytes (magic + dimensions + reserved fields +
bitmap size)
- Bit polarity: 0 = black, 1 = white
- No runtime text rendering needed - pages display directly on e-ink
- Faster page display compared to EPUB since no parsing/rendering
required
- Memory efficient: loads one page at a time (48KB per page)
- Tested with XTC files generated from https://x4converter.rho.sh/
- Verified correct page alignment and color rendering
- Please report any issues if you test with XTC files from other
sources.
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* Use font ascender height for baseline offset
* Previously was using font height, but when rendering the font (even
from y = 0), there would be a lot of top margin
* Font would also go below the "bottom of the line" as we were using the
full font height as the baseline
## Additional Context
* This caused some text to move around, I've fixed everything I can
* Notably it moves the first line of font a little closer to the top of
the page
• What is the goal of this PR?
Implement a horizontal EPUB reading mode so books can be read in
landscape orientation (both 90° and 270°), while keeping the rest of the
UI in portrait.
• What changes are included?
◦ Rendering / Display
▪ Added an orientation model to GfxRenderer (Portrait, LandscapeNormal,
LandscapeFlipped) and made:
▪ drawPixel, drawImage, displayWindow map logical coordinates
differently depending on orientation.
▪ getScreenWidth() / getScreenHeight() return orientation‑aware logical
dimensions (480×800 in portrait, 800×480 in landscape).
◦ Settings / Configuration
▪ Extended CrossPointSettings with:
▪ landscapeReading (toggle for portrait vs. landscape EPUB reading).
▪ landscapeFlipped (toggle to flip landscape 180° so both horizontal
holding directions are supported).
▪ Updated settings serialization/deserialization to persist these fields
while remaining backward‑compatible with existing settings files.
▪ Updated SettingsActivity to expose two new toggles:
▪ “Landscape Reading”
▪ “Flip Landscape (swap top/bottom)”
◦ EPUB Reader
▪ In EpubReaderActivity:
▪ On onEnter, set GfxRenderer orientation based on the new settings
(Portrait, LandscapeNormal, or LandscapeFlipped).
▪ On onExit, reset orientation back to Portrait so Home, WiFi, Settings,
etc. continue to render as before.
▪ Adjusted renderStatusBar to position the status bar and battery
indicator relative to GfxRenderer::getScreenHeight() instead of
hard‑coded Y coordinates, so it stays correctly at the bottom in both
portrait and landscape.
◦ EPUB Caching / Layout
▪ Extended Section cache metadata (section.bin) to include the logical
screenWidth and screenHeight used when pages were generated; bumped
SECTION_FILE_VERSION.
▪ Updated loadCacheMetadata to compare:
▪ font/margins/line compression/extraParagraphSpacing and screen
dimensions; mismatches now invalidate and clear the cache.
▪ Updated persistPageDataToSD and all call sites in EpubReaderActivity
to pass the current GfxRenderer::getScreenWidth() / getScreenHeight() so
portrait and landscape caches are kept separate and correctly sized.
Additional Context
• Cache behavior / migration
◦ Existing section.bin files (old SECTION_FILE_VERSION) will be detected
as incompatible and their caches cleared and rebuilt once per chapter
when first opened after this change.
◦ Within a given orientation, caches will be reused as before. Switching
orientation (portrait ↔ landscape) will cause a one‑time re‑index of
each chapter in the new orientation.
• Scope and risks
◦ Orientation changes are scoped to the EPUB reader; the Home screen,
Settings, WiFi selection, sleep screens, and web server UI continue to
assume portrait orientation.
◦ The renderer’s orientation is a static/global setting; if future code
uses GfxRenderer outside the reader while a reader instance is active,
it should be aware that orientation is no longer implicitly fixed.
◦ All drawing primitives now go through orientation‑aware coordinate
transforms; any code that previously relied on edge‑case behavior or
out‑of‑bounds writes might surface as logged “Outside range” warnings
instead.
• Testing suggestions / areas to focus on
◦ Verify in hardware:
▪ Portrait mode still renders correctly (boot, home, settings, WiFi,
reader).
▪ Landscape reading in both directions:
▪ Landscape Reading = ON, Flip Landscape = OFF.
▪ Landscape Reading = ON, Flip Landscape = ON.
▪ Status bar (page X/Y, % progress, battery icon) is fully visible and
aligned at the bottom in all three combinations.
◦ Open the same book:
▪ In portrait first, then switch to landscape and reopen it.
▪ Confirm that:
▪ Old portrait caches are rebuilt once for landscape (you should see the
“Indexing…” page).
▪ Progress save/restore still works (resume opens to the correct page in
the current orientation).
◦ Ensure grayscale rendering (the secondary pass in
EpubReaderActivity::renderContents) still looks correct in both
orientations.
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Summary
* **What is the goal of this PR?**
Replace simple threshold-based grayscale quantization with ordered
dithering using a 4x4 Bayer matrix. This eliminates color banding
artifacts and produces smoother gradients on e-ink display.
* **What changes are included?**
- Add 4x4 Bayer dithering matrix for 16-level threshold patterns
- Modify `grayscaleTo2Bit()` function to accept pixel coordinates and
apply position-based dithering
- Replace simple `grayscale >> 6` threshold with ordered dithering
algorithm that produces smoother gradients
## Additional Context
* Bayer matrix approach: The 4x4 Bayer matrix creates a repeating
pattern that distributes quantization error spatially, effectively
simulating 16 levels of gray using only 4 actual color levels (black,
dark gray, light gray, white).
* Cache invalidation: Existing cached `cover.bmp` files will need to be
deleted to see the improved rendering, as the converter only runs when
the cache is missing.
## Summary
This creates a `renderer.drawButtonHints` to make all of the "hints"
over buttons to match the home screen.
## Additional Context
* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks, specific areas to
focus on).
---------
Co-authored-by: Dave Allie <dave@daveallie.com>
## Problem
`drawBmp()` allocates two row buffers via `malloc()` but doesn't check
if allocations succeed. On low memory, this causes a crash when the NULL
pointers are dereferenced.
## Fix
Add NULL check after both `malloc()` calls. If either fails, log error
and return early.
Changed `lib/GfxRenderer/GfxRenderer.cpp`.
## Test
- Defensive addition only - no logic changes
- Manual device testing appreciated
## Problem
`invertScreen()`, `storeBwBuffer()`, and `restoreBwBuffer()` dereference
`frameBuffer` without NULL validation. If the display isn't initialized,
these functions will crash.
## Fix
Add NULL checks before using `frameBuffer` in all three functions.
Follows the existing pattern from `drawPixel()` (line 11) which already
validates the pointer.
Changed `lib/GfxRenderer/GfxRenderer.cpp`.
## Test
- Follows existing validated pattern from `drawPixel()`
- No logic changes - only adds early return on NULL
- Manual device testing appreciated
## Summary
- When allocating the `bwBuffer` required to restore the RED RAM in the
EPD, we were previously allocating the whole frame buffer in one
contiguous memory chunk (48kB)
- Depending on the state of memory fragmentation at the time of this
call, it may not be possible to allocate all that memory
- Instead, we now allocate 6 blocks of 8kB instead of the full 48kB,
this should mean the display updates are more resilient to different
memory conditions
## Additional Context
