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Move to SDK EInkDisplay and enable anti-aliased 2-bit text (#5)

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* First pass at moving to SDK EInkDisplay library

* Add 2-bit grayscale text and anti-aliased rendering of text

* Render status bar for empty chapters

* Refresh screen every 15 pages to avoid ghosting

* Simplify boot and sleep screens

* Give FileSelectionScreen task more stack memory

* Move text around slightly on Boot and Sleep screens

* Re-use existing buffer and write to whole screen for 'partial update'
This commit is contained in:
Dave Allie
2025-12-08 19:48:49 +11:00
committed by GitHub
parent de453fed1d
commit 2ed8017aa2
31 changed files with 11300 additions and 9243 deletions
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77
lib/EpdFontRenderer/EpdFontRenderer.hpp
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@@ -6,22 +6,27 @@
inline int min(const int a, const int b) { return a < b ? a : b; }
inline int max(const int a, const int b) { return a > b ? a : b; }
enum EpdFontRendererMode { BW, GRAYSCALE_LSB, GRAYSCALE_MSB };
template <typename Renderable>
class EpdFontRenderer {
Renderable& renderer;
void renderChar(uint32_t cp, int* x, const int* y, uint16_t color, EpdFontStyle style = REGULAR);
void renderChar(uint32_t cp, int* x, const int* y, bool pixelState, EpdFontStyle style = REGULAR,
EpdFontRendererMode mode = BW);
public:
const EpdFontFamily* fontFamily;
explicit EpdFontRenderer(const EpdFontFamily* fontFamily, Renderable& renderer)
: fontFamily(fontFamily), renderer(renderer) {}
~EpdFontRenderer() = default;
void renderString(const char* string, int* x, int* y, uint16_t color, EpdFontStyle style = REGULAR);
void renderString(const char* string, int* x, int* y, bool pixelState = true, EpdFontStyle style = REGULAR,
EpdFontRendererMode mode = BW);
void drawPixel(int x, int y, bool pixelState);
};
template <typename Renderable>
void EpdFontRenderer<Renderable>::renderString(const char* string, int* x, int* y, const uint16_t color,
const EpdFontStyle style) {
void EpdFontRenderer<Renderable>::renderString(const char* string, int* x, int* y, const bool pixelState,
const EpdFontStyle style, const EpdFontRendererMode mode) {
// cannot draw a NULL / empty string
if (string == nullptr || *string == '\0') {
return;
@@ -34,15 +39,49 @@ void EpdFontRenderer<Renderable>::renderString(const char* string, int* x, int*
uint32_t cp;
while ((cp = utf8NextCodepoint(reinterpret_cast<const uint8_t**>(&string)))) {
renderChar(cp, x, y, color, style);
renderChar(cp, x, y, pixelState, style, mode);
}
*y += fontFamily->getData(style)->advanceY;
}
// TODO: Consolidate this with EpdRenderer implementation
template <typename Renderable>
void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const int* y, uint16_t color,
const EpdFontStyle style) {
void EpdFontRenderer<Renderable>::drawPixel(const int x, const int y, const bool pixelState) {
uint8_t* frameBuffer = renderer.getFrameBuffer();
// Early return if no framebuffer is set
if (!frameBuffer) {
Serial.printf("!!No framebuffer\n");
return;
}
// Bounds checking (portrait: 480x800)
if (x < 0 || x >= EInkDisplay::DISPLAY_HEIGHT || y < 0 || y >= EInkDisplay::DISPLAY_WIDTH) {
Serial.printf("!!Outside range (%d, %d)\n", x, y);
return;
}
// Rotate coordinates: portrait (480x800) -> landscape (800x480)
// Rotation: 90 degrees clockwise
const int16_t rotatedX = y;
const int16_t rotatedY = EInkDisplay::DISPLAY_HEIGHT - 1 - x;
// Calculate byte position and bit position
const uint16_t byteIndex = rotatedY * EInkDisplay::DISPLAY_WIDTH_BYTES + (rotatedX / 8);
const uint8_t bitPosition = 7 - (rotatedX % 8); // MSB first
// Set or clear the bit
if (pixelState) {
frameBuffer[byteIndex] &= ~(1 << bitPosition); // Clear bit
} else {
frameBuffer[byteIndex] |= (1 << bitPosition); // Set bit
}
}
template <typename Renderable>
void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const int* y, const bool pixelState,
const EpdFontStyle style, const EpdFontRendererMode mode) {
const EpdGlyph* glyph = fontFamily->getGlyph(cp, style);
if (!glyph) {
// TODO: Replace with fallback glyph property?
@@ -55,6 +94,7 @@ void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const in
return;
}
const int is2Bit = fontFamily->getData(style)->is2Bit;
const uint32_t offset = glyph->dataOffset;
const uint8_t width = glyph->width;
const uint8_t height = glyph->height;
@@ -70,11 +110,26 @@ void EpdFontRenderer<Renderable>::renderChar(const uint32_t cp, int* x, const in
const int pixelPosition = glyphY * width + glyphX;
int screenX = *x + left + glyphX;
const uint8_t byte = bitmap[pixelPosition / 8];
const uint8_t bit_index = 7 - (pixelPosition % 8);
if (is2Bit) {
const uint8_t byte = bitmap[pixelPosition / 4];
const uint8_t bit_index = (3 - pixelPosition % 4) * 2;
if ((byte >> bit_index) & 1) {
renderer.drawPixel(screenX, screenY, color);
const uint8_t val = (byte >> bit_index) & 0x3;
if (mode == BW && val > 0) {
drawPixel(screenX, screenY, pixelState);
} else if (mode == GRAYSCALE_MSB && val == 1) {
// TODO: Not sure how this anti-aliasing goes on black backgrounds
drawPixel(screenX, screenY, false);
} else if (mode == GRAYSCALE_LSB && val == 2) {
drawPixel(screenX, screenY, false);
}
} else {
const uint8_t byte = bitmap[pixelPosition / 8];
const uint8_t bit_index = 7 - (pixelPosition % 8);
if ((byte >> bit_index) & 1) {
drawPixel(screenX, screenY, pixelState);
}
}
}
}