Basic draw NDS functions

/*Basic draw functions by xerpi*/

#include <nds.h>
#include <stdio.h>

void drawLine(int x0, int y0, int x, int y, unsigned int color);
void drawHline(int y, int x0, int x1, unsigned int color);
void drawVline(int x, int y0, int y1, unsigned int color);
void drawPlot(int x, int y, unsigned int color);
void drawRect(int x, int y, int w, int h, unsigned int color);
void drawFillRect(int x, int y, int w, int h, unsigned int color);

int main(void){
    int i;
    touchPosition touch;
    consoleDemoInit();
    videoSetMode(MODE_FB0 | DISPLAY_BG3_ACTIVE);
    vramSetBankA(VRAM_A_LCD);

    printf("Basic draw functions by xerpi!\n");

    for(i = 0; i < 256 * 192; i++)
        VRAM_A[i] = RGB15(31,0,0);

    drawRect( 10, 10, 20, 80, RGB15(0, 31, 0));
    drawFillRect( 100, 100, 50, 30, RGB15(0, 0, 31));
    drawLine( 0, 0, 255, 192, RGB15(0, 0, 31));
    drawPlot(255, 191, RGB15(0, 0, 31));


    while(1){
        scanKeys();
        consoleClear();
        printf("Basic draw functions by xerpi!\n");
        if(keysHeld() & KEY_TOUCH)
            touchRead(&touch);
        printf("x: %i y: %i!\n", touch.px, touch.py);
        VRAM_A[touch.px + touch.py * 256] = rand();
        if(keysHeld() & KEY_A)
            printf("Key A is pressed");
        swiWaitForVBlank();
    }

    return 0;
}


void drawLine(int x0, int y0, int x, int y, unsigned int color){
    if(x == x0){
        drawVline(x0, y0, y, color);
        return;
    }

    if(y == y0){
        drawHline(y0, x0, x, color);
        return;
    }
    int i, x_dist, y_dist;
    float ratio;

    if(x0 > x)
        x_dist = x0 - x;
    else
        x_dist = x - x0;
    if(y0 > y)
        y_dist = y0 - y;
    else
        y_dist = y - y0;

    ratio = (float)x_dist/(float)y_dist;

    for(i = 0; i < y_dist; i++){
        VRAM_A[ (int)(x0 + i * ratio) + (int)(y0 + i*256)] = color;
    }
}


void drawPlot(int x, int y, unsigned int color){
    VRAM_A[x + y*256] = color;
}

void drawHline(int y, int x0, int x1, unsigned int color){
    int i;
    if(x0 < x1)
        for(i = x0; i < x1; i++)
            VRAM_A[i + y*256] = color;
    else
        for(i = x1; i < x0; i++)
            VRAM_A[i + y*256] = color;

}


void drawVline(int x, int y0, int y1, unsigned int color){
    int i;
    if(y0 < y1)
        for(i = y0; i < y1; i++)
            VRAM_A[x + i*256] = color;
    else
        for(i = y1; i < y0; i++)
            VRAM_A[x + i*256] = color;

}

void drawRect(int x, int y, int w, int h, unsigned int color){
    drawVline(x, y, y + h, color);
    drawVline(x + w, y, y + h, color);
    drawHline(y + h, x, x + w, color);
    drawHline(y, x, x + w, color);
}

void drawFillRect(int x, int y, int w, int h, unsigned int color){
    int i;
    for(i = y; i < y + h; i++)
        drawHline(i, x, x + w, color);

}