textbuffer.c

#include "textbuffer.h"
#include "gfx.h"
#include <string.h>

void txt_init(struct txt_buffer *txtb, struct gfx_region *reg, sFONT *f)
{
	txtb->reg           = reg;
	txtb->font          = f;
	txtb->cursor_column = 0;
	txtb->cursor_row    = 0;
	txtb->fg_color      = gfx_color_rgb_f(reg, 1.0f, 1.0f, 1.0f);
	txtb->bg_color      = gfx_color_rgb_f(reg, .0f, .0f, .0f);
	txtb->draw_cursor   = 1;
	txtb->auto_update   = 1;
}

static inline size_t width_(struct txt_buffer *tm)
{
	return tm->reg->width / tm->font->Width;
}

static inline size_t height_(struct txt_buffer *tm)
{
	return tm->reg->height / tm->font->Height;
}

size_t txt_width(struct txt_buffer *tm)
{
	return width_(tm);
}

size_t txt_height(struct txt_buffer *tm)
{
	return height_(tm);
}

static void scrollup(struct txt_buffer *tm)
{
	const int last_row     = height_(tm) - 1;
	const size_t line_size = width_(tm) * sizeof(struct txt_glyph);

	for (int row = 0; row < last_row; row++)
		memcpy(&tm->text[row][0], &tm->text[row + 1][0], line_size);
	for (int col = 0; col < width_(tm); col++) {
		struct txt_glyph *g = &tm->text[last_row][col];
		g->ch               = ' ';
		g->fg_color         = tm->fg_color;
		g->bg_color         = tm->bg_color;
	}
}

static void newline(struct txt_buffer *tm)
{
	const int last_row = height_(tm) - 1;

	scrollup(tm);
	tm->cursor_row    = last_row;
	tm->cursor_column = 0;
}

static inline void advance_cursor(struct txt_buffer *tm)
{
	const int last_row = height_(tm) - 1;

	tm->cursor_column++;
	if (tm->cursor_column >= width_(tm)) {
		tm->cursor_column = 0;
		tm->cursor_row++;
		if (tm->cursor_row > last_row)
			newline(tm);