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Character rendering optimizations and off-by-one fix #27

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Character rendering optimizations and off-by-one fix #27

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aa45690
Optimize lcd_write_char by using lcd_draw_image (indirectly using i2c…
slyglif Jan 4, 2024
388c6ca
Fix bug in lcd_draw_image
slyglif Jan 4, 2024
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33 changes: 17 additions & 16 deletions hardware/st7735/st7735.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
#include "st7735.h"
#include "time.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sysinfo.h>
#include <sys/vfs.h>
Expand Down Expand Up @@ -40,25 +41,28 @@ void lcd_set_address_window(uint8_t x0, uint8_t y0, uint8_t x1, uint8_t y1)
*/
void lcd_write_char(uint16_t x, uint16_t y, char ch, FontDef font, uint16_t color, uint16_t bgcolor)
{
uint32_t i, b, j;
size_t fbsize = font.height * font.width * sizeof(uint16_t);
uint16_t *buff;
uint32_t i, b, j, offset;

lcd_set_address_window(x, y, x + font.width - 1, y + font.height - 1);
/* Allocate a buffer to hold the screen data */
buff = malloc(fbsize);
if (!buff) return;

/* Render the character to the buffer */
for (i = 0; i < font.height; i++)
{
offset = i * font.width;
b = font.data[(ch - 32) * font.height + i];
for (j = 0; j < font.width; j++)
{
if ((b << j) & 0x8000)
{
i2c_write_data(color >> 8, color & 0xFF);
}
else
{
i2c_write_data(bgcolor >> 8, bgcolor & 0xFF);
}
buff[offset + j] = ((b << j) & 0x8000) ? color : bgcolor;
}
}

/* Push the image to the screen */
lcd_draw_image(x, y, font.width, font.height, (uint8_t*)buff);
free(buff);
}

void lcd_write_ch(uint16_t x, uint16_t y, char ch, FontType font, uint16_t color, uint16_t bgcolor)
Expand Down Expand Up @@ -106,7 +110,6 @@ void lcd_write_string(uint16_t x, uint16_t y, char *str, FontDef font, uint16_t
}

lcd_write_char(x, y, *str, font, color, bgcolor);
i2c_write_command(SYNC_REG, 0x00, 0x01);
x += font.width;
str++;
}
Expand Down Expand Up @@ -141,9 +144,9 @@ void lcd_fill_rectangle(uint16_t x, uint16_t y, uint16_t w, uint16_t h, uint16_t
// clipping
if ((x >= ST7735_WIDTH) || (y >= ST7735_HEIGHT))
return;
if ((x + w - 1) >= ST7735_WIDTH)
if ((x + w) >= ST7735_WIDTH)
w = ST7735_WIDTH - x;
if ((y + h - 1) >= ST7735_HEIGHT)
if ((y + h) >= ST7735_HEIGHT)
h = ST7735_HEIGHT - y;
lcd_set_address_window(x, y, x + w - 1, y + h - 1);

Expand All @@ -170,10 +173,8 @@ void lcd_fill_screen(uint16_t color)

void lcd_draw_image(uint16_t x, uint16_t y, uint16_t w, uint16_t h, uint8_t *data)
{
uint16_t col = h - y;
uint16_t row = w - x;
lcd_set_address_window(x, y, x + w - 1, y + h - 1);
i2c_burst_transfer(data, sizeof(uint16_t) * col * row);
i2c_burst_transfer(data, sizeof(uint16_t) * w * h);
}

uint8_t lcd_begin(void)
Expand Down