自由線の太さを変更

#include "sptk.h"

#define WIDTH  300
#define HEIGHT 300
#define PIXCOL 0x0000ff

int lastx,lasty;
int drawsize = 1;

unsigned char bit_1px[1] = {0x80};
unsigned char bit_2px[2] = {0xc0,0xc0};
unsigned char bit_3px[3] = {0x40,0xe0,0x40};
unsigned char bit_4px[4] = {0x60,0xf0,0xf0,0x60};

unsigned char *bit_array[4] = {bit_1px, bit_2px, bit_3px, bit_4px};

void drawpoint(SPTK_IMAGE *img,int x,int y,uint32_t col,int size)
{
    int ix,iy,f;
    unsigned char *p;
    
    x -= size / 2;
    y -= size / 2;
    
    p = bit_array[size - 1];
    
    for(iy = 0; iy < size; iy++, p++)
    {
        f = 0x80;

        for(ix = 0; ix < size; ix++, f >>= 1)
        {
            if(*p & f)
                sptk_image_setpixel(img, x + ix, y + iy, col);
        }
    }
}

void drawline(SPTK_IMAGE *img,int x1,int y1,int x2,int y2,uint32_t col,int size)
{
    int dx,dy,sx,sy,a,a1,e;
        
    if(x1 <= x2)
        dx = x2 - x1, sx = 1;
    else
        dx = x1 - x2, sx = -1;

    if(y1 <= y2)
        dy = y2 - y1, sy = 1;
    else
        dy = y1 - y2, sy = -1;
    
    if(dx >= dy)
    {
        a  = 2 * dy;
        a1 = a - 2 * dx;
        e  = a - dx;
    
        while(1)
        {
            drawpoint(img, x1, y1, col, size);
            
            if(x1 == x2) break;
            
            if(e >= 0) y1 += sy, e += a1;
            else e += a;
            
            x1 += sx;
        }
    }
    else
    {
        a  = 2 * dx;
        a1 = a - 2 * dy;
        e  = a - dy;
        
        while(1)
        {
            drawpoint(img, x1, y1, col, size);
            
            if(y1 == y2) break;
            
            if(e >= 0) x1 += sx, e += a1;
            else e += a;
            
            y1 += sy;
        }
    }
}

void winhandle(SPTK_EVENT *ev)
{
    SPTK_RECT rc;
    int half;

    switch(ev->type)
    {
        case SPTK_EVENT_BTTDOWN:
            if(ev->mouse.btt == SPTK_MOUSEBTT_LEFT)
            {
                lastx = ev->mouse.x;
                lasty = ev->mouse.y;
                
                sptk_grab(NULL);
            }
            break;
        case SPTK_EVENT_BTTUP:
            if(ev->mouse.btt == SPTK_MOUSEBTT_LEFT && sptk_isgrab())
                sptk_ungrab();
            break;
        case SPTK_EVENT_MOUSEMOVE:
            if(sptk_isgrab())
            {
                rc.x1 = lastx;
                rc.y1 = lasty;
                rc.x2 = ev->mouse.x;
                rc.y2 = ev->mouse.y;
            
                drawline(sptk_window_get_image(),
                    rc.x1, rc.y1, rc.x2, rc.y2, PIXCOL, drawsize);
                
                /* 更新 */
                
                sptk_rect_swap(&rc);
                
                half = drawsize / 2;
                
                rc.x1 -= half;
                rc.y1 -= half;
                rc.x2 += drawsize - half - 1;
                rc.y2 += drawsize - half - 1;
                
                sptk_update_rect(NULL, &rc, 0);
                
                lastx = ev->mouse.x;
                lasty = ev->mouse.y;
            }
            break;

        case SPTK_EVENT_WINDOW_KEYDOWN:
            if(ev->key.code >= '1' && ev->key.code <= '4')
                drawsize = ev->key.code - '0';
            break;
    
        case SPTK_EVENT_WINDOW_CLOSE:
            sptk_quit();
            break;
    }
}

int main()
{
    sptk_init("test", WIDTH, HEIGHT);
    
    sptk_window_set_handle(winhandle);
    
    sptk_run();

    return 0;
}