drawing_text.c

Text rendering with built-in fonts, ANSI colours, and printf-style formatting.

Text rendering with built-in fonts, ANSI colours, and printf-style formatting.Banjo includes bitmap text rendering with a built-in font. No external font files are needed. Text can be rendered with ANSI escape codes for inline colours, printf-style formatting, and various transparency modes.

 
#include <banjo/app.h>
#include <banjo/main.h>
#include <banjo/bitmap.h>
#include <banjo/event.h>
#include <banjo/log.h>
#include <banjo/system.h>
#include <banjo/window.h>
 
bj_window* window = 0;
void draw(bj_bitmap* bmp) {
 
    uint32_t white      = bj_make_bitmap_pixel(bmp,255,255,255);
    uint32_t black      = bj_make_bitmap_pixel(bmp,0,0,0);
    uint32_t light_grey = bj_make_bitmap_pixel(bmp,220,220,220);
    uint32_t cyan       = bj_make_bitmap_pixel(bmp,0,200,200);
 
    // bj_draw_text() renders text with ANSI escape code support for inline
    // colours. Use \x1B[<code>m for colours and \x1B[0m to reset to default.
    // Parameters: bitmap, x, y, size, foreground_color, text
    bj_draw_text(bmp, 20, 20,  18, white, "\x1B[31mRED\x1B[0m normal");
    bj_draw_text(bmp, 20, 52,  18, white, "\x1B[94mBrightBlue\x1B[0m + default");
    bj_draw_text(bmp, 20, 84,  18, white, "\x1B[38;2;255;128;0mTruecolor Orange\x1B[0m");
 
    // bj_draw_textf() works like printf, supporting all standard format
    // specifiers. This is the easiest way to display dynamic values like
    // scores, health, coordinates, etc.
    bj_draw_textf(bmp, 20, 200, 18, white, "Hello, %s!", "world");
    bj_draw_textf(bmp, 20, 230, 18, white, "Score: %d  Lives: %u", -123, 3);
    bj_draw_textf(bmp, 20, 260, 18, white, "Zero-pad: %08u  Left: %-8u|", 42, 42);
    bj_draw_textf(bmp, 20, 290, 18, white, "Name: %.5s  Pi≈%.3f (note: if %%f not supported, skip)", "Banjo", 3.14159);
    bj_draw_textf(bmp, 20, 320, 18, white, "HEX: 0x%08X  oct: %o  ptr: %p", 0xDEADBEEF, 0755, (void*)bmp);
    bj_draw_textf(bmp, 20, 350, 18, white, "Width(*)=%*u  Prec(*)=%. *u", 6, 123, 4, 123);
 
    // Length modifiers (ll, l, h, hh) are supported for different integer sizes.
    unsigned long long big = 18446744073709551615ull;
    bj_draw_textf(bmp, 20, 380, 18, white, "ll: %llu  l: %ld  h: %hd  hh: %hhu",
                     big, (long)-123456, (short)1234, (unsigned char)255);
 
    // bj_blit_text() provides more control with separate foreground and
    // background colours and transparency modes:
    //   BJ_MASK_BG_OPAQUE - solid background rectangle
    //   BJ_MASK_BG_REV_TRANSPARENT - background shows through foreground
    bj_blit_text(bmp, 20, 116, 14, black, light_grey, BJ_MASK_BG_OPAQUE, "OPAQUE band (FG black)");
    bj_blit_text(bmp, 20, 150, 32, black, cyan, BJ_MASK_BG_REV_TRANSPARENT, "CARVED cyan");
}
 
static void on_draw(
    struct bj_window*        w,
    struct bj_render_target* target,
    const struct bj_rect*    dirty,
    void*                    user_data
) {
    (void)w; (void)dirty; (void)user_data;
    draw(bj_render_target_bitmap(target));
}
 
static void* setup(struct bj_app* app, void* init_data) {
    (void)init_data;
 
    if (!bj_begin(BJ_VIDEO_SYSTEM, 0)) {
        bj_quit_app(app, 1);
        return 0;
    }
 
    window = bj_bind_window("Simple Text", 100, 100, 500, 500, 0, 0);
 
    bj_set_key_callback(bj_close_on_escape, 0);
    bj_set_draw_callback(window, on_draw, 0);
    bj_invalidate_window(window);
    return 0;
}
 
static void step(struct bj_app* app, struct bj_tick_info tick, void* user_data) {
    (void)tick;
    (void)user_data;
    bj_dispatch_events();
 
    if (bj_should_close_window(window)) {
        bj_quit_app(app, 0);
    }
}
 
static void teardown(struct bj_app* app, void* user_data) {
    (void)user_data;
    bj_unbind_window(window);
    bj_end();
}
 
int main(int argc, char* argv[]) {
    (void)argc; (void)argv;
    return bj_run_app(setup, step, 0, teardown, 0);
}