C++ draw_pixel函数代码示例

void InterpolateVideo::draw_line(VFrame *frame, int x1, int y1, int x2, int y2)
{
	int w = labs(x2 - x1);
	int h = labs(y2 - y1);
//printf("InterpolateVideo::draw_line 1 %d %d %d %d\n", x1, y1, x2, y2);

	if(!w && !h)
	{
		draw_pixel(frame, x1, y1);
	}
	else
	if(w > h)
	{
// Flip coordinates so x1 < x2
		if(x2 < x1)
		{
			y2 ^= y1;
			y1 ^= y2;
			y2 ^= y1;
			x1 ^= x2;
			x2 ^= x1;
			x1 ^= x2;
		}
		int numerator = y2 - y1;
		int denominator = x2 - x1;
		for(int i = x1; i < x2; i++)
		{
			int y = y1 + (int64_t)(i - x1) * (int64_t)numerator / (int64_t)denominator;
			draw_pixel(frame, i, y);
		}
	}
	else
	{
// Flip coordinates so y1 < y2
		if(y2 < y1)
		{
			y2 ^= y1;
			y1 ^= y2;
			y2 ^= y1;
			x1 ^= x2;
			x2 ^= x1;
			x1 ^= x2;
		}
		int numerator = x2 - x1;
		int denominator = y2 - y1;
		for(int i = y1; i < y2; i++)
		{
			int x = x1 + (int64_t)(i - y1) * (int64_t)numerator / (int64_t)denominator;
			draw_pixel(frame, x, i);
		}
	}
//printf("InterpolateVideo::draw_line 2\n");
}

void draw_rect(int x1, int y1, int width, int height, color_t c) {
    int vert =0;
    int hori = 0;
    for(hori = x1; hori < width+x1; hori++) {
        draw_pixel(hori,y1,c);
        draw_pixel(hori,y1+height,c);
    }
    for(vert =y1; vert<height+y1; vert++) {
        draw_pixel(x1, vert, c);
        draw_pixel(x1+width, vert,c);
    }
}

void
draw_line(
	color24_t c,
	uint32_t x0,
	uint32_t y0,
	uint32_t x1,
	uint32_t y1
)
{
	const int32_t dx = abs(x1 - x0);
	const int32_t dy = abs(y1 - y0);

	const int32_t sx = x0 < x1 ? 1 : -1;
	const int32_t sy = y0 < y1 ? 1 : -1;
	int32_t err = dx - dy;

#if VSCREEN_SHIFT != 0
	uint32_t last_px = -1;
	uint32_t last_py = -1;
#endif

	while(1)
	{
#if VSCREEN_SHIFT != 0
		uint32_t px = x0 >> VSCREEN_SHIFT;
		uint32_t py = y0 >> VSCREEN_SHIFT;
		if (px != last_px || py != last_py)
		{
			last_px = px;
			last_py = py;
			draw_pixel(c, x0, y0);
		}
#else
		draw_pixel(c, x0, y0);
#endif

		if (x0 == x1 && y0 == y1)
			break;
		int32_t e2 = 2 * err;
		if (e2 > -dy)
		{
			err -= dy;
			x0 += sx;
		}
		if (e2 < +dx)
		{
			err += dx;
			y0 += sy;
		}
	}
}

void draw_rect(int x1, int y1, int width, int height, color_t c){
  int x = 0;
  int y = 0;

  for(x = x1; x <= width+1; x++){
    draw_pixel(x, y1, c);
    draw_pixel(x, y1 + height, c);
  }

  for(y = y1; y <= height+2; y++){
    draw_pixel(x1, y, c);
    draw_pixel(x1 + width, y, c);
  }
}

bool Pattern_peak_spike::display()
{
#undef LOG_PEAKS
#ifdef LOG_PEAKS
    const int max_dots = 64;
    char dots[max_dots + 2];
    memset(dots, ' ', sizeof(dots));
    dots[max_dots] = '|';
    dots[max_dots + 1] = '\0';
    memset(dots, '.', get_mapped_peak(max_dots));
    Serial.printf("peak %5u %s\n", get_peak(), dots);
#endif

    Colour c = make_hue(g_hue.get());

    int leds = get_mapped_peak(LED_COUNT / 2);

#define FADE_PEAK
#ifdef FADE_PEAK
    static Value held_leds(0, 0, LED_COUNT / 2);
    held_leds.set_velocity(-10, 60);
    if (leds > held_leds.get()) {
	held_leds.set(leds);
    }
    leds = held_leds.get();
#endif

    // Start drawing out from the bottom middle both up and horizontally.
    int start_x = COLUMN_COUNT / 2;
    int start_y = ROW_COUNT - 1;
    int x = start_x;
    int y = start_y;
    for (int led = 0; led < leds; ++led) {
	draw_pixel(x, y, c);
	draw_pixel(flip_x(x), y, c);
	++x;
	++y;
	if (x >= COLUMN_COUNT || y >= ROW_COUNT) {
	    --start_y;
	    if (start_y < 0) {
		start_y = 0;
		++start_x;
	    }
	    x = start_x;
	    y = start_y;
	}
    }

    return true;
}

static void inline draw_blocks(uint8_t blocks[][4]) {
    uint8_t i, j;
    for (i = 0; i < 4; i++) {
        for (j = 0; j < 4; j++) {
            if (blocks[i][j]) {
                draw_pixel(2*i, j+4, cff5500);
                draw_pixel(2*i+1, j+4, cff5500);
            } else {
                draw_pixel(2*i, j+4, c000000);
                draw_pixel(2*i+1, j+4, c000000);
            }
        }
    }
}

/**
 * @param surface cíl
 * @param x1 počáteční souřadnice úsečky
 * @param y1 počáteční souřadnice
 * @param x2 koncové souřadnice úsečky
 * @param y2 koncové souřadnice úsečky
 * @param color barva úsečky
 */
void draw_line(SDL_Surface* surface, int x1, int y1, int x2, int y2, SDL_Color color){
	// pres parametrickou rovnici usecky
	// kazdy bod Z usecky AB se spocita
	// Z = A + (B-A)t
	// pro 0<= t <= 1
	int length, w=(x2-x1), h=(y2-y1), t;
	// length= sqrt(w^2+h^2);
		length= w*w + h*h;
		for( t=0 ; t*t<length ; ++t); length=t;
	// vhodne zdrobnely parametr vykresli dostatecne mnoho pixelu
	if(length){
		for( t=0 ; t<=length ; ++t )
			draw_pixel(surface, x1 + w*t/length, y1 + h*t/length ,color);
	} else	draw_pixel(surface, x1, y1 ,color);
}

void print_character(uint16_t *colour_ptr, uint32_t x, uint32_t y, volatile unsigned char *fb) {
  for (int i = 0; i < CHAR_WIDTH; ++i) {
    for (int j = 0; j < CHAR_HEIGHT; ++j) {
      draw_pixel(x + j, y + i, fb, colour_ptr[j + (i * CHAR_WIDTH)]);
    }
  }
}

void
Canvas::fill_rect(uint8_t x, uint8_t y, uint8_t width, uint8_t height)
{
    for (uint8_t i = 0; i < width; i++)
        for (uint8_t j = 0; j < height; j++)
            draw_pixel(x + i, y + j);
}

void smooth_buffer(struct pixel_buffer* pix) {

	int x,y;
	
	for (x = 0; x < pix->width; x++) {
		
		for (y = 0; y < pix->height; y++) {
			
			int left = (x - 1) % pix->width;
			int right = (x + 1) % pix->width;
			int up 	= (y - 1) % pix->height;
			int down = (y + 1) % pix->height;

			if (left < 0) {
				
				left = left + pix->width;
			}
			
			if (up < 0) {
				
				up = up + pix->height;
			}

			Uint32 val = (get_pixel(pix, x, up) + get_pixel(pix, x, down) + get_pixel(pix, left, y) + get_pixel(pix, right, y)) / 4;
			
			draw_pixel(pix, x, y, val);
		}
	}
}

static void	fract_j(t_env *env, t_fract fr)
{
	double	rn1;
	double	in1;
	double	rn;
	double	in;
	int		a;

	rn1 = 2.0 * (fr.x - env->win_x / 2) / (0.5 * env->zoom * env->win_x) +
		env->pos_x;
	in1 = (fr.y - env->win_y / 2) / (0.5 * env->zoom * env->win_y) + env->pos_y;
	a = -1;
	while (++a < (env->iter - 1))
	{
		rn = rn1;
		in = in1;
		rn1 = (rn * rn) - (in * in) + fr.rc;
		in1 = 2 * rn * in + fr.ic;
		if ((rn1 * rn1 + in1 * in1) > 4)
			break ;
	}
	get_color_palette(env, env->color, a, env->pal);
	if ((fr.x >= 0 && fr.x < env->win_x) && (fr.y >= 0 && fr.y < env->win_y)
			&& a < (env->iter - 1))
		draw_pixel(env, fr.x, fr.y, env->color);
}

static void	draw_wall(t_event *e, t_raycast *rc, t_vec2 *p, int line_height)
{
	int	color;
	int id;

	if (!e->texture_mode)
	{
		if (rc->side)
			color = rc->step.y > 0 ? 0xff0000 : 0xffff00;
		else
			color = rc->step.x > 0 ? 0x00ff00 : 0x00ffff;
	}
	else
	{
		id = e->game.map[rc->map.y][rc->map.x];
		rc->tex.y = (p->y * 2 - e->height + line_height)
			* (e->textures[id].height / 2) / line_height;
		color = e->textures[id].data[rc->tex.y
			* e->textures[id].width + rc->tex.x];
		if (rc->side)
			color = color_fusion(color, 0x0f0f0f);
		else
			color = color_fusion(color, 0x1f1f1f);
	}
	draw_pixel(e, p->x, p->y, color);
	free(p);
}

static inline void draw_xy(int x, int y,
			unsigned char r,
			unsigned char g,
			unsigned char b)
{
	draw_pixel(x + centerX, centerY - y, r, g, b);
}

	void press_event(MouseEvent ev)
	{
		pressed = true;
		draw_pixel(ev.x, ev.y);
		last_x = ev.x;
		last_y = ev.y;
	}

void draw_bitmap(uint32_t x, uint32_t y, uint32_t width, uint32_t height, uint16_t *sprite, volatile unsigned char *fb) {
  for (int i = 0; i < width; ++i) {
    for (int j = 0; j < height; ++j) {
      draw_pixel(x + i, y + j, fb, sprite[i + (width * j)]);
    }
  }
}