Re: Graphics on LCD

[Shang-te Hsu]

Hi,
    The attached file is a LCD test program. Please using "arm-linux-gcc -static
-o lcdtest lcdtest.c"
to compile and test it. Linux/Brutus uses frame buffer in LCD. Each pixel in
frame buffer is a color index.

Shang-te Hsu.

Harsha Sanjeewa wrote:

> Hi everybody,
>    I want to do graphics on  LCD that comes with Brutus board. Can some
> one tell me from where
> should I start. I also want to know where can I get information about
> kernel header files. I cant figure out what the funcitons are actually
> doing, especially fb.h .
> Regards
> Harsha
>
> unsubscribe: body of `unsubscribe linux-arm' to [EMAIL PROTECTED]
> ++        Please use [EMAIL PROTECTED] for           ++
> ++                        kernel-related discussions.                      ++

#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <signal.h>
#include <sys/time.h>
#define MAX_X   320
#define MAX_Y   240
#define MAX_SIZE        (MAX_X * MAX_Y)
#define SWAP(x1, y1, x2, y2, tmp) {\
        tmp = x1; \
        x1 = x2; \
        x2 = tmp; \
        tmp = y1; \
        y1 = y2; \
        y2 = tmp; }

char *fbp;

int draw_pixel(int x, int y, unsigned char color_index)
{
        if ((x < 0) || (y < 0) || (x >= MAX_X) || (y >= MAX_Y))
                return -1;

        *(fbp + y * MAX_X + x) = color_index;
}


int h_line(int x, int y, int length, unsigned char color_index)
{
        int i;

        if (length <= 0)
                return -1;

        for (i=x;i<(x+length);i++)
                draw_pixel(i, y, color_index);
}

int v_line(int x, int y, int length, unsigned char color_index)
{
        int i;

        if (length <= 0)
                return -1;

        for (i=y;i<(y+length);i++)
                draw_pixel(x, i, color_index);
}

int box(int x, int y, int dx, int dy, unsigned char color_index)
{
        h_line(x,       y,      dx, color_index);
        h_line(x,  y+dy-1,      dx, color_index);
        v_line(x,     y+1,    dy-1, color_index);
        v_line(x+dx-1,y+1,    dy-1, color_index);
}

int two_point_line(int x1, int y1, int x2, int y2, unsigned char color_index)
{
        int t,x,y,dx,dy,sign,i,e;

        if (x1 == x2) {
                if (y1 == y2)
                        draw_pixel(x1, y1, color_index);
                else
                        v_line(x1, (y1 > y2)? y2:y1, abs(y1 - y2), color_index);
        } else if (y1 == y2) {
                        h_line((x1 > x2)? x2:x1, y1, abs(x1 - x2), color_index);
        }

        dx = abs(x2 - x1);
        dy = abs(y2 - y1);

        if (dx >= dy) { /* x-major */
                e = dy - dx;
                if (x1 > x2)
                        SWAP(x1, y1, x2, y2, t);

                sign = (y1 > y2)? -1 : 1;
                x = x1;
                y = y1;
                for (i=0;i<dx;i++,x++,e += dy) {
                        draw_pixel(x, y, color_index);
                        if (e >= 0) {
                                y += sign;
                                e -= dx;
                        }
                }
        } else { /* y-major */
                e = dx - dy;
                if (y1 > y2)
                        SWAP(x1, y1, x2, y2, t);

                sign = (x1 > x2)? -1 : 1;
                x = x1;
                y = y1;
                for (i=0;i<dy;i++,y++, e += dx) {
                        draw_pixel(x, y, color_index);
                        if (e >= 0) {
                                x += sign;
                                e -= dy;
                        }
                }
        }
}
int
FillRectangleSolid(int x, int y, int width, int height, unsigned char color)
{
        int i;
        if ((width <= 0) || (height <= 0))
                return -1;
        for (i=0;i<height;i++)
                h_line(x, y+i, width, color);
}

main()
{
        int f;
        int i,j,color;
        int x,y,w,h;
        int x1,y1,x2,y2;
        f = open("/dev/fb", O_RDWR);

        if (f < 0) {
                printf("Can't open /dev/fb\n");
                exit(1);
        }
        fbp = mmap(0, MAX_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, f, 0);
        if ((int)fbp < 0) {
                printf("Can't mmap /dev/fb\n");
                exit(1);
        }
        for (i=0;i<16;i++) {
                for (j=0;j<16;j++) {
                        FillRectangleSolid(
                                j*20,
                                i*15,
                                20, 15, i*16+j);
                }
        }
#if 0
        while (1) {
#if 0
                x = random()%MAX_X;
                y = random()%MAX_Y;
                w = random()%50;
                h = random()%50;
                color = random()%16;
                FillRectangleSolid(x,y, w, h, color);
#endif
                x1 = random()%MAX_X;
                x2 = random()%MAX_X;
                y1 = random()%MAX_Y;
                y2 = random()%MAX_Y;
                color = random()%255;
                two_point_line(x1, y1, x2, y2, color);
                usleep(8000);
                two_point_line(x1, y1, x2, y2, 0);
                usleep(8000);
        }
#endif
        close(f);
}