lineutil

lineutil.h

#ifndef LINEUTIL_H
#define LINEUTIL_H

#include "common.h"
/*
** Draws horizontal line
** hexRgb = e.g. 0xFF0000
*/

void drawHLine(int x1, int x2, int y, GLubyte *data, unsigned long hexRgb, int width, int height)
{
    GLubyte red, green, blue;
    red = hexRgb >> 16;
    green = (hexRgb & 0x00ff00) >> 8;
    blue = (hexRgb & 0x0000ff);

    //Make sure Y-value is legit
    if (y >= 0 && y < height) {
        //Make sure x1 < x2
        if (x2 < x1) {
            int tmp = x1;
            x1 = x2;
            x2 = tmp;
        }
        //Make sure at least part of the line is inside the height*width area
        if (!(x1 < 0 && x2 < 0) && !(x1 > width - 1 && x2 > width - 1)) {
            //Clamp right adn left edge values
            if (x1 < 0) {
                x1 = 0;
            }
            if (x2 > width-1) {
                x2 = width-1;
            }
            //render the line
            GLubyte* ptr = &data[(y * width + x1) * BYTES_PER_COLOR];
            GLubyte* end = &data[(y * width + x2 + 1) * BYTES_PER_COLOR];
            while (ptr < end) {
                *ptr++ = red;
                *ptr++ = green;
                *ptr++ = blue;
                *ptr++ = 0xFF;
            }
        }
    }
}

/*
** Draws vertical line
** hexRgb = e.g. 0xFF0000
*/

void drawVLine(int x1, int y1, int y2, GLubyte *data, unsigned long hexRgb, int width, int height)
{
    GLubyte red, green, blue;
    red = hexRgb >> 16;
    green = (hexRgb & 0x00ff00) >> 8;
    blue = (hexRgb & 0x0000ff);

    //Make sure the line is legit
    if (x1 >= 0 && x1 < width) {
        //Make sure y1 < y2
        if (y1 > y2) {
            int tmp = y1;
            y1 = y2;
            y2 = tmp;
        }
        //Make sure part of the line is in the image area
        if (!(y1 < 0 && y2 < 0) && !(y1 > height - 1 && y2 > height - 1)) {
            //clamp values vertically
            if (y1 < 0) {
                y1 = 0;
            }
            if (y2 > height - 1) {
                y2 = height - 1;
            }

            //render
            GLubyte *ptr = &data[(y1 * width + x1) * BYTES_PER_COLOR];
            int height = y2 - y1 + 1;

            for (int i = 0; i < height; i++) {
                *ptr++ = red;
                *ptr++ = green;
                *ptr++ = blue;
                *ptr++ = 0xFF;
                ptr += (BYTES_PER_COLOR * width - BYTES_PER_COLOR);
            }
        }
    }

}

#endif // LINEUTIL_H