生成灰阶测试图

程序员文章站 2022-05-12 08:40:08

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代码

* Generate YUV420P gray scale bar.
* @param width    Width of Output YUV file.
* @param height   Height of Output YUV file.
* @param ymin     Max value of Y
* @param ymax     Min value of Y
* @param barnum   Number of bars
* @param url_out  Location of Output YUV file.
*/
int simplest_yuv420_graybar(int width, int height,int ymin,int ymax,int barnum,char *url_out){
int barwidth;
float lum_inc;
unsigned char lum_temp;
int uv_width,uv_height;
FILE *fp=NULL;
unsigned char *data_y=NULL;
unsigned char *data_u=NULL;
unsigned char *data_v=NULL;
int t=0,i=0,j=0;

barwidth=width/barnum;
lum_inc=((float)(ymax-ymin))/((float)(barnum-1));
uv_width=width/2;
uv_height=height/2;

data_y=(unsigned char *)malloc(width*height);
data_u=(unsigned char *)malloc(uv_width*uv_height);
data_v=(unsigned char *)malloc(uv_width*uv_height);

if((fp=fopen(url_out,"wb+"))==NULL){
    printf("Error: Cannot create file!");
    return -1;
}

//Output Info
printf("Y, U, V value from picture's left to right:\n");
for(t=0;t<(width/barwidth);t++){
    lum_temp=ymin+(char)(t*lum_inc);
    printf("%3d, 128, 128\n",lum_temp);
}
//Gen Data
for(j=0;j<height;j++){
    for(i=0;i<width;i++){
        t=i/barwidth;
        lum_temp=ymin+(char)(t*lum_inc);
        data_y[j*width+i]=lum_temp;
    }
}
for(j=0;j<uv_height;j++){
    for(i=0;i<uv_width;i++){
        data_u[j*uv_width+i]=128;
    }
}
for(j=0;j<uv_height;j++){
    for(i=0;i<uv_width;i++){
        data_v[j*uv_width+i]=128;
    }
}
fwrite(data_y,width*height,1,fp);
fwrite(data_u,uv_width*uv_height,1,fp);
fwrite(data_v,uv_width*uv_height,1,fp);
fclose(fp);
free(data_y);
free(data_u);
free(data_v);
return 0;
}