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Font rendering.
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@tzarc
tzarc committed Jan 10, 2022
1 parent df2e581 commit 45463d8
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5 changes: 5 additions & 0 deletions quantum/painter/qp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -160,3 +160,8 @@ painter_font_handle_t qp_load_font_mem(const void QP_RESIDENT_FLASH_OR_RAM *buff

// Closes a font handle when no longer in use. Returns true if successfully closed.
bool qp_close_font(painter_font_handle_t font);

// Draw text to the display
int16_t qp_textwidth(painter_font_handle_t font, const char QP_RESIDENT_FLASH_OR_RAM *str);
int16_t qp_drawtext(painter_device_t device, uint16_t x, uint16_t y, painter_font_handle_t font, const char QP_RESIDENT_FLASH_OR_RAM *str);
int16_t qp_drawtext_recolor(painter_device_t device, uint16_t x, uint16_t y, painter_font_handle_t font, const char QP_RESIDENT_FLASH_OR_RAM *str, uint8_t hue_fg, uint8_t sat_fg, uint8_t val_fg, uint8_t hue_bg, uint8_t sat_bg, uint8_t val_bg);
307 changes: 307 additions & 0 deletions quantum/painter/qp_draw_text.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@

#include <qp_internal.h>
#include <qp_draw.h>
#include <qp_comms.h>
#include <qff.h>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
Expand Down Expand Up @@ -129,3 +130,309 @@ bool qp_close_font(painter_font_handle_t font) {
qff_font->validate_ok = false;
return true;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Helpers

// Callback to be invoked for each codepoint detected in the UTF8 input string
typedef bool (*code_point_handler)(qff_font_handle_t *qff_font, uint32_t code_point, uint8_t width, uint8_t height, void *cb_arg);

// Helper that sets up the palette (if required) and returns the offset in the stream that the data starts
static inline bool qp_drawtext_prepare_font_for_render(painter_device_t device, qff_font_handle_t *qff_font, qp_pixel_t fg_hsv888, qp_pixel_t bg_hsv888, uint32_t *data_offset) {
struct painter_driver_t *driver = (struct painter_driver_t *)device;

// Drop out if we can't actually place the data we read out anywhere
if (!data_offset) {
qp_dprintf("Failed to prepare stream for read, output info buffer unavailable\n");
return false;
}

// Work out where we're reading from
uint32_t offset = sizeof(qff_font_descriptor_v1_t);
if (qff_font->has_ascii_table) {
offset += sizeof(qff_ascii_glyph_table_v1_t);
}
if (qff_font->num_unicode_glyphs > 0) {
offset += sizeof(qff_unicode_glyph_table_v1_t) + (qff_font->num_unicode_glyphs * 6);
}

// Handle palette if needed
const uint16_t palette_entries = 1u << qff_font->bpp;
bool needs_pixconvert = false;
if (qff_font->has_palette) {
// If this font has a palette, we need to read it out and set up the pixel lookup table
qp_stream_setpos(&qff_font->stream, offset);
if (!qp_internal_load_qgf_palette(&qff_font->stream, qff_font->bpp)) {
return false;
}

// Skip this block, as far as offset calculations go
offset += sizeof(qgf_palette_v1_t) + (palette_entries * 3);
needs_pixconvert = true;
} else {
// Interpolate from fg/bg
int16_t palette_entries = 1 << qff_font->bpp;
needs_pixconvert = qp_internal_interpolate_palette(fg_hsv888, bg_hsv888, palette_entries);
}

if (needs_pixconvert) {
// Convert the palette to native format
if (!driver->driver_vtable->palette_convert(device, palette_entries, qp_internal_global_pixel_lookup_table)) {
qp_dprintf("qp_drawtext_recolor: fail (could not convert pixels to native)\n");
qp_comms_stop(device);
return false;
}
}

*data_offset = offset;
return true;
}

static inline bool qp_drawtext_prepare_glyph_for_render(qff_font_handle_t *qff_font, uint32_t code_point, uint8_t *width) {
if (code_point >= 0x20 && code_point < 0x7F && qff_font->has_ascii_table) {
// Do ascii table
qff_ascii_glyph_v1_t glyph_info;
uint32_t glyph_info_offset = sizeof(qff_font_descriptor_v1_t) // Skip the font descriptor
+ sizeof(qgf_block_header_v1_t) // Skip the ascii table header
+ (code_point - 0x20) * sizeof(qff_ascii_glyph_v1_t); // Jump direct to the data offset based on the glyph index
if (qp_stream_setpos(&qff_font->stream, glyph_info_offset) < 0) {
qp_dprintf("Failed to set stream position while reading ascii glyph info\n");
return false;
}

if (qp_stream_read(&glyph_info, sizeof(qff_ascii_glyph_v1_t), 1, &qff_font->stream) != 1) {
qp_dprintf("Failed to read glyph info\n");
return false;
}

uint8_t glyph_width = (uint8_t)(glyph_info.value & QFF_GLYPH_WIDTH_MASK);
uint32_t glyph_offset = ((glyph_info.value & QFF_GLYPH_OFFSET_MASK) >> QFF_GLYPH_WIDTH_BITS);
uint32_t data_offset = sizeof(qff_font_descriptor_v1_t) // Skip the font descriptor
+ sizeof(qff_ascii_glyph_table_v1_t) // Skip the ascii table
+ (qff_font->num_unicode_glyphs > 0 ? (sizeof(qff_unicode_glyph_table_v1_t) + (qff_font->num_unicode_glyphs * sizeof(qff_unicode_glyph_v1_t))) : 0) // Skip the unicode table
+ (qff_font->has_palette ? (sizeof(qgf_palette_v1_t) + ((1 << qff_font->bpp) * sizeof(qgf_palette_entry_v1_t))) : 0) // Skip the palette
+ sizeof(qgf_block_header_v1_t) // Skip the data block header
+ glyph_offset; // Jump to the specified glyph offset

if (qp_stream_setpos(&qff_font->stream, data_offset) < 0) {
qp_dprintf("Failed to set stream position while preparing ascii glyph data\n");
return false;
}

*width = glyph_width;
return true;
} else {
// Do unicode table, which may include singular ascii glyphs if full ascii table isn't specified
uint32_t glyph_info_offset = sizeof(qff_font_descriptor_v1_t) // Skip the font descriptor
+ (qff_font->has_ascii_table ? sizeof(qff_ascii_glyph_table_v1_t) : 0) // Skip the ascii table
+ sizeof(qgf_block_header_v1_t); // Skip the unicode block header

if (qp_stream_setpos(&qff_font->stream, glyph_info_offset) < 0) {
qp_dprintf("Failed to set stream position while preparing glyph data\n");
return false;
}

qff_unicode_glyph_v1_t glyph_info;
for (uint16_t i = 0; i < qff_font->num_unicode_glyphs; ++i) {
if (qp_stream_read(&glyph_info, sizeof(qff_unicode_glyph_v1_t), 1, &qff_font->stream) != 1) {
qp_dprintf("Failed to set stream position while reading unicode glyph info\n");
return false;
}

if (glyph_info.code_point == code_point) {
uint8_t glyph_width = (uint8_t)(glyph_info.value & QFF_GLYPH_WIDTH_MASK);
uint32_t glyph_offset = ((glyph_info.value & QFF_GLYPH_OFFSET_MASK) >> QFF_GLYPH_WIDTH_BITS);
uint32_t data_offset = sizeof(qff_font_descriptor_v1_t) // Skip the font descriptor
+ sizeof(qff_ascii_glyph_table_v1_t) // Skip the ascii table
+ (qff_font->num_unicode_glyphs > 0 ? (sizeof(qff_unicode_glyph_table_v1_t) + (qff_font->num_unicode_glyphs * sizeof(qff_unicode_glyph_v1_t))) : 0) // Skip the unicode table
+ (qff_font->has_palette ? (sizeof(qgf_palette_v1_t) + ((1 << qff_font->bpp) * sizeof(qgf_palette_entry_v1_t))) : 0) // Skip the palette
+ sizeof(qgf_block_header_v1_t) // Skip the data block header
+ glyph_offset; // Jump to the specified glyph offset

if (qp_stream_setpos(&qff_font->stream, data_offset) < 0) {
qp_dprintf("Failed to set stream position while preparing unicode glyph data\n");
return false;
}

*width = glyph_width;
return true;
}
}

// Not found
qp_dprintf("Failed to find unicode glyph info\n");
return false;
}
return false;
}

// Function to iterate over each UTF8 codepoint, invoking the callback for each decoded glyph
static inline bool qp_iterate_code_points(qff_font_handle_t *qff_font, const char QP_RESIDENT_FLASH_OR_RAM *str, code_point_handler handler, void *cb_arg) {
while (*str) {
int32_t code_point = 0;
str = decode_utf8(str, &code_point);
if (code_point < 0) {
qp_dprintf("Invalid unicode code point decoded. Cannot render.\n");
return false;
}

uint8_t width;
if (!qp_drawtext_prepare_glyph_for_render(qff_font, code_point, &width)) {
qp_dprintf("Failed to prepare glyph for rendering.\n");
return false;
}

if (!handler(qff_font, code_point, width, qff_font->base.line_height, cb_arg)) {
qp_dprintf("Failed to execute glyph handler.\n");
return false;
}
}
return true;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// String width calculation

// Callback state
struct code_point_iter_calcwidth_state {
int16_t width;
};

// Codepoint handler callback: width calc
static inline bool qp_font_code_point_handler_calcwidth(qff_font_handle_t *qff_font, uint32_t code_point, uint8_t width, uint8_t height, void *cb_arg) {
struct code_point_iter_calcwidth_state *state = (struct code_point_iter_calcwidth_state *)cb_arg;

// Increment the overall width by this glyph's width
state->width += width;

return true;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// String drawing implementation

// Callback state
struct code_point_iter_drawglyph_state {
painter_device_t device;
int16_t xpos;
int16_t ypos;
qp_internal_byte_input_callback input_callback;
struct qp_internal_byte_input_state * input_state;
struct qp_internal_pixel_output_state *output_state;
};

// Codepoint handler callback: drawing
static inline bool qp_font_code_point_handler_drawglyph(qff_font_handle_t *qff_font, uint32_t code_point, uint8_t width, uint8_t height, void *cb_arg) {
struct code_point_iter_drawglyph_state *state = (struct code_point_iter_drawglyph_state *)cb_arg;
struct painter_driver_t * driver = (struct painter_driver_t *)state->device;

// Reset the input state's RLE mode -- the stream should already be correctly positioned by qp_iterate_code_points()
state->input_state->rle.mode = MARKER_BYTE; // ignored if not using RLE

// Reset the output state
state->output_state->pixel_write_pos = 0;

// Configure where we're going to be rendering to
driver->driver_vtable->viewport(state->device, state->xpos, state->ypos, state->xpos + width - 1, state->ypos + height - 1);

// Move the x-position for the next glyph
state->xpos += width;

// Decode the pixel data for the glyph
uint32_t pixel_count = ((uint32_t)width) * height;
bool ret = qp_internal_decode_palette(state->device, pixel_count, qff_font->bpp, state->input_callback, state->input_state, qp_internal_global_pixel_lookup_table, qp_internal_pixel_appender, state->output_state);

// Any leftovers need transmission as well.
if (ret && state->output_state->pixel_write_pos > 0) {
ret &= driver->driver_vtable->pixdata(state->device, qp_internal_global_pixdata_buffer, state->output_state->pixel_write_pos);
}

return ret;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Quantum Painter External API: qp_textwidth

int16_t qp_textwidth(painter_font_handle_t font, const char QP_RESIDENT_FLASH_OR_RAM *str) {
qff_font_handle_t *qff_font = (qff_font_handle_t *)font;
if (!qff_font->validate_ok) {
qp_dprintf("qp_textwidth: fail (invalid font)\n");
return false;
}

// Create the codepoint iterator state
struct code_point_iter_calcwidth_state state = {.width = 0};
// Iterate each codepoint, return the calculated width if successful.
return qp_iterate_code_points(qff_font, str, qp_font_code_point_handler_calcwidth, &state) ? state.width : 0;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Quantum Painter External API: qp_drawtext

int16_t qp_drawtext(painter_device_t device, uint16_t x, uint16_t y, painter_font_handle_t font, const char QP_RESIDENT_FLASH_OR_RAM *str) {
// Offload to the recolor variant, substituting fg=white bg=black.
// Traditional LCDs with those colors will need to manually invoke qp_drawtext_recolor with the colors reversed.
return qp_drawtext_recolor(device, x, y, font, str, 0, 0, 255, 0, 0, 0);
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Quantum Painter External API: qp_drawtext_recolor

int16_t qp_drawtext_recolor(painter_device_t device, uint16_t x, uint16_t y, painter_font_handle_t font, const char QP_RESIDENT_FLASH_OR_RAM *str, uint8_t hue_fg, uint8_t sat_fg, uint8_t val_fg, uint8_t hue_bg, uint8_t sat_bg, uint8_t val_bg) {
qp_dprintf("qp_drawtext_recolor: entry\n");
struct painter_driver_t *driver = (struct painter_driver_t *)device;
if (!driver->validate_ok) {
qp_dprintf("qp_drawtext_recolor: fail (validation_ok == false)\n");
return 0;
}

qff_font_handle_t *qff_font = (qff_font_handle_t *)font;
if (!qff_font->validate_ok) {
qp_dprintf("qp_drawtext_recolor: fail (invalid font)\n");
return false;
}

if (!qp_comms_start(device)) {
qp_dprintf("qp_drawtext_recolor: fail (could not start comms)\n");
return 0;
}

// Set up the byte input state and input callback
struct qp_internal_byte_input_state input_state = {.device = device, .src_stream = &qff_font->stream};
qp_internal_byte_input_callback input_callback = qp_internal_prepare_input_state(&input_state, qff_font->compression_scheme);
if (input_callback == NULL) {
qp_dprintf("qp_drawtext_recolor: fail (invalid font compression scheme)\n");
qp_comms_stop(device);
return false;
}

// Set up the pixel output state
struct qp_internal_pixel_output_state output_state = {.device = device, .pixel_write_pos = 0, .max_pixels = qp_internal_num_pixels_in_buffer(device)};

// Set up the codepoint iteration state
struct code_point_iter_drawglyph_state state = {// Common
.device = device,
.xpos = x,
.ypos = y,
// Input
.input_callback = input_callback,
.input_state = &input_state,
// Output
.output_state = &output_state};

qp_pixel_t fg_hsv888 = {.hsv888 = {.h = hue_fg, .s = sat_fg, .v = val_fg}};
qp_pixel_t bg_hsv888 = {.hsv888 = {.h = hue_bg, .s = sat_bg, .v = val_bg}};
uint32_t data_offset;
if (!qp_drawtext_prepare_font_for_render(driver, qff_font, fg_hsv888, bg_hsv888, &data_offset)) {
qp_dprintf("qp_drawtext_recolor: fail (failed to prepare font for rendering)\n");
qp_comms_stop(device);
return false;
}

// Iterate the codepoints with the drawglyph callback
bool ret = qp_iterate_code_points(qff_font, str, qp_font_code_point_handler_drawglyph, &state);

qp_dprintf("qp_drawtext_recolor: %s\n", ret ? "ok" : "fail");
qp_comms_stop(device);
return ret ? (state.xpos - x) : 0;
}

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