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ESC/P 2: Fix dot size and non-adjacent mode with graphics #6784

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Merged
OBattler merged 1 commit into from
Feb 7, 2026
Merged

ESC/P 2: Fix dot size and non-adjacent mode with graphics #6784

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73 changes: 39 additions & 34 deletions src/printer/prt_escp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -151,8 +151,8 @@ enum {

/* Some helper macros. */
#define PARAM16(x) (dev->esc_parms[x + 1] * 256 + dev->esc_parms[x])
#define PIXX ((unsigned) floor(dev->curr_x * dev->dpi + 0.5))
#define PIXY ((unsigned) floor(dev->curr_y * dev->dpi + 0.5))
#define PIXX ((unsigned) round(dev->curr_x * dev->dpi))
#define PIXY ((unsigned) round(dev->curr_y * dev->dpi))

typedef struct psurface_t {
int8_t dirty; /* has the page been printed on? */
Expand Down Expand Up @@ -204,10 +204,11 @@ typedef struct escp_t {
/* bit graphics data */
uint16_t bg_h_density; /* in dpi */
uint16_t bg_v_density; /* in dpi */
int8_t bg_adjacent; /* print adjacent pixels (ignored) */
int8_t bg_adjacent; /* print adjacent pixels */
uint8_t bg_bytes_per_column;
uint16_t bg_remaining_bytes; /* #bytes left before img is complete */
uint8_t bg_column[6]; /* #bytes of the current and last col */
uint8_t bg_previous[6]; // for non-adjacent pixels in graphics mode
uint8_t bg_bytes_read; /* #bytes read so far for current col */

/* handshake data */
Expand Down Expand Up @@ -402,13 +403,11 @@ timeout_timer(void *priv)
static void
fill_palette(uint8_t redmax, uint8_t greenmax, uint8_t bluemax, uint8_t colorID, escp_t *dev)
{
uint8_t colormask;
const uint8_t colormask = colorID <<= 5;

double red = (double) redmax / (double) 30.9;
double green = (double) greenmax / (double) 30.9;
double blue = (double) bluemax / (double) 30.9;

colormask = colorID <<= 5;
const double red = (double) redmax / (double) 30.9;
const double green = (double) greenmax / (double) 30.9;
const double blue = (double) bluemax / (double) 30.9;

for (uint8_t i = 0; i < 32; i++) {
dev->palcol[i + colormask].r = 255 - (uint8_t) floor(red * (double) i);
Expand Down Expand Up @@ -777,6 +776,8 @@ setup_bit_image(escp_t *dev, uint8_t density, uint16_t num_columns)
escp_log("ESC/P: Unsupported bit image density %d.\n", density);
break;
}
for (uint8_t i = 0; i < dev->bg_bytes_per_column; ++i)
dev->bg_previous[i] = 0;

dev->bg_remaining_bytes = num_columns * dev->bg_bytes_per_column;
dev->bg_bytes_read = 0;
Expand Down Expand Up @@ -1879,27 +1880,25 @@ draw_hline(escp_t *dev, unsigned from_x, unsigned to_x, unsigned y, int8_t broke
static void
print_bit_graph(escp_t *dev, uint8_t ch)
{
uint8_t pixel_w; /* width of the "pixel" */
uint8_t pixel_h; /* height of the "pixel" */
double old_y;

dev->bg_column[dev->bg_bytes_read++] = ch;
dev->bg_remaining_bytes--;

/* Only print after reading a full column. */
if (dev->bg_bytes_read < dev->bg_bytes_per_column)
return;

old_y = dev->curr_y;
/* vertical density is how big the dot is
* (horziontal / vertical / 2) is how many middle points between two full dots are
* if horizontal < vertical, this means a column is printed multiple times
*/
uint8_t dot_size_x;
const uint8_t dot_size_y = round((double) dev->dpi / (double) dev->bg_v_density);
if (dev->bg_h_density < dev->bg_v_density)
dot_size_x = round((double) dev->dpi / (double) dev->bg_h_density);
else
dot_size_x = dot_size_y;

pixel_w = 1;
pixel_h = 1;

if (dev->bg_adjacent) {
/* if page DPI is bigger than bitgraphics DPI, drawn pixels get "bigger" */
pixel_w = dev->dpi / dev->bg_h_density > 0 ? dev->dpi / dev->bg_h_density : 1;
pixel_h = dev->dpi / dev->bg_v_density > 0 ? dev->dpi / dev->bg_v_density : 1;
}
const double old_y = dev->curr_y;

for (uint8_t i = 0; i < dev->bg_bytes_per_column; i++) {
/* for each byte */
Expand All @@ -1908,11 +1907,21 @@ print_bit_graph(escp_t *dev, uint8_t ch)
break;
/* for each bit */
if (dev->bg_column[i] & j) {
/* draw a "pixel" */
for (uint8_t xx = 0; xx < pixel_w; xx++) {
for (uint8_t yy = 0; yy < pixel_h; yy++) {
if (((PIXX + xx) < (unsigned) dev->page->w) && ((PIXY + yy) < (unsigned) dev->page->h))
*((uint8_t *) dev->page->pixels + (PIXX + xx) + (PIXY + yy) * dev->page->pitch) |= (dev->color | 0x1f);
if (!(dev->bg_adjacent) && (dev->bg_previous[i] & j)) {
dev->bg_column[i] &= ~j;
dev->curr_y += 1.0 / (double) dev->bg_v_density;
continue;
}
/* draw a dot */
for (uint8_t xx = 0; xx < dot_size_x; ++xx) {
if ((PIXX + xx) >= (unsigned) dev->page->w)
break;

for (uint8_t yy = 0; yy < dot_size_y; ++yy) {
if ((PIXY + yy) >= (unsigned) dev->page->h)
break;

*((uint8_t *) dev->page->pixels + (PIXX + xx) + (PIXY + yy) * dev->page->pitch) |= (dev->color | 0x1f);
}
}
}
Expand All @@ -1921,6 +1930,8 @@ print_bit_graph(escp_t *dev, uint8_t ch)
}
}

memcpy(dev->bg_previous, dev->bg_column, dev->bg_bytes_per_column * sizeof(uint8_t));

/* Mark page dirty. */
dev->page->dirty = 1;

Expand Down Expand Up @@ -2229,14 +2240,13 @@ escp_init(const device_t *info)
memset(dev->page->pixels, 0x00, (size_t) dev->page->pitch * dev->page->h);

/* Initialize parameters. */
/* 0 = all white needed for logic 000 */
for (uint8_t i = 0; i < 32; i++) {
dev->palcol[i].r = 255;
dev->palcol[i].g = 255;
dev->palcol[i].b = 255;
}

/* 0 = all white needed for logic 000 */
fill_palette(0, 0, 0, 1, dev);
/* 1 = magenta* 001 */
fill_palette(0, 255, 0, 1, dev);
/* 2 = cyan* 010 */
Expand Down Expand Up @@ -2290,11 +2300,6 @@ escp_close(void *priv)
}

// clang-format off
#if 0
static const device_config_t lpt_prt_escp_config[] = {
{ .name = "", .description = "", .type = CONFIG_END }
};
#endif
static const device_config_t lpt_prt_escp_config[] = {
{
.name = "language",
Expand Down
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