void pixMap_rotate (pixMap *p, float theta){
//correct rotation that uses inverse rotation to determine which pixels to copy from the original
//the previous method would leave holes in the image
pixMap *temp=pixMap_init();//make a new temp blank pixMap structure
pixMap_copy(temp,p); //copy the p to temp
//set the values in the image to zero using memset - that the 3rd argument of memset is the size in BYTES
memset(temp->image,0,temp->width*temp->height*sizeof(rgba));
const float ox=p->width/2.0f;
const float oy=p->height/2.0f;
const float s=sin(degreesToRadians(-theta));
const float c=cos(degreesToRadians(-theta));
//for() //double for loop to loop through each pixel in the original
//for()
//calculate the old coordinates rotx roty to copy from using the formula from
//http://stackoverflow.com/questions/2259476/rotating-a-point-about-another-point-2d
//use the answer from stackoverflowery
//round the coordinates to the nearest integer in your calculations (add 0.5 and cast to integer)
//if rotated coordinates are still inside the image
//copy the pixel at the old coords to the pixel to the temporary copy using memcpy
//i.e. memcpy(temp->pixArray[y]+x,p->pixArray[roty]+rotx,sizeof(rgba))
//
//
//
//copy the temp pixMap to the original
//destroy the temp
for(int y=0;y<p->height;y++){
for(int x=0;x<p->width;x++){
float rotx = c*(x-ox) - s * (oy-y) + ox;
float roty = -(s*(x-ox) + c * (oy-y) - oy);
int rotj=rotx+.5;
int roti=roty+.5;
if(roti >=0 && roti < temp->height && rotj >=0 && rotj < temp->width){
memcpy(temp->pixArray[y]+x,p->pixArray[roti]+rotj,sizeof(rgba));
}
}
}
pixMap_copy(p,temp);
pixMap_destroy(temp);
return;
}
int main(int argc, char *argv[]) {
char *inputfile = 0, *outputfile = 0;
float degrees = 0, grayFlag = 0;
int count;
for(count = 0; count < argc; count++) {
/*Print arguments for reference*/
//fprintf(stderr, "argv[%d] %s \n", count, argv[count]);
/*Check for input*/
if(strcmp(argv[count], "-i") == 0) {
inputfile = argv[count + 1];
count++;
/*Check for output*/
} else if(strcmp(argv[count], "-o") == 0) {
outputfile = argv[count + 1];
count++;
/*Check for rotate*/
} else if(strcmp(argv[count], "-r") == 0) {
degrees = strtof(argv[count + 1], NULL);
count++;
/*Check for gray*/
} else if(strcmp(argv[count], "-g") == 0) {
grayFlag = 1;
count++;
}
}
pixMap *p=pixMap_init_filename(inputfile);
if(degrees)pixMap_rotate(p,degrees);
if(grayFlag)pixMap_gray(p);
pixMap_write(p,outputfile);
pixMap_destroy(p);
return 0;
}
