I'm trying to write a function in swift, which returns a CGPoint where the extension of a vector (which is within a screen) will intersect the screen. Let's assume that the screen is 800 x 600. It's like the scheme:
The function should have the following parameters:
func calcPoint(start: CGPoint, end: CGPoint) -> CGPoint
start: CGPoint(x: x1, y: y1) - this is the beginning of the vector.
end: CGPoint(x: x1, y: y1) - this is the end point of the vector.
the return point is the one at which the vector intersects the screen (CGPoint(x: x3, y: y3) as shown at the scheme).
The values for the vector start and end are aways points within the screen (the rectangle 0, 0, 800, 600).
EDIT (for Alexander):
Is there a formula, which in the given situation will make it easy to write the function, in not the obvious way using if ... else ... and triangle vertices ratio?
To compute point E you can look at the triangles given by your setting. You have the Triangle ABC and DBE. Note that they are similar, such that we can set up following relation AB : AC = DB : DE using the intercept theorem (AB etc. stands for the line segment between A and B). In the given setting you know all points but E.
Using start and end Points from given setting:
In case start and end have the same x or y-coordinate it is only the top bottom or left right border with the same coordinate.
Using the absolute values it should work for all four corners of your rectangle. Then of course you have to consider E being out of your rectangle, again the same relation can be used AB : AC = D'B : D'E'
A pure swift solution for everyone interested in such (thanks to Ivo Ivanoff):
// Example for iOS
/// The height of the screen
let screenHeight = UIScreen.main.bounds.height
/// The width of the screen
let screenWidth = UIScreen.main.bounds.width
func calculateExitPoint(from anchor : CGPoint, to point: CGPoint) -> CGPoint {
var exitPoint : CGPoint = CGPoint()
let directionV: CGFloat = anchor.y < point.y ? 1 : -1
let directionH: CGFloat = anchor.x < point.x ? 1 : -1
let a = directionV > 0 ? screenHeight - anchor.y : anchor.y
let a1 = directionV > 0 ? point.y - anchor.y : anchor.y - point.y
let b1 = directionH > 0 ? point.x - anchor.x : anchor.x - point.x
let b = a / (a1 / b1)
let tgAlpha = b / a
let b2 = directionH > 0 ? screenWidth - point.x : point.x
let a2 = b2 / tgAlpha
exitPoint.x = anchor.x + b * directionH
exitPoint.y = point.y + a2 * directionV
if (exitPoint.x > screenWidth) {
exitPoint.x = screenWidth
} else if (exitPoint.x < 0) {
exitPoint.x = 0;
} else {
exitPoint.y = directionV > 0 ? screenHeight : 0
}
return exitPoint
}
Any kind of optimizations are welcomed ;-)
There is no single formula, because intersection depends on starting point position, line slope and rectangle size, and it may occur at any rectangle edge.
Here is approach based on parametric representation of line. Works for any slope (including horizontal and vertical). Finds what border is intersected first, calculates intersection point.
dx = end.x - start.x
dy = end.y - start.y
//parametric equations for reference:
//x = start.x + dx * t
//y = start.y + dy * t
//prerequisites: potential border positions
if dx > 0 then
bx = width
else
bx = 0
if dy > 0 then
by = height
else
by = 0
//first check for horizontal/vertical lines
if dx = 0 then
return ix = start.x, iy = by
if dy = 0 then
return iy = start.y, ix = bx
//in general case find parameters of intersection with horizontal and vertical edge
tx = (bx - start.x) / dx
ty = (by - start.y) / dy
//and get intersection for smaller parameter value
if tx <= ty then
ix = bx
iy = start.y + tx * dy
else
iy = by
ix = start.x + ty * dx
return ix, iy
I am following the quaternion tutorial: http://www.raywenderlich.com/12667/how-to-rotate-a-3d-object-using-touches-with-opengl and am trying to rotate a globe to some XYZ location. I have an initial quaternion and generate a random XYZ location on the surface of the globe. I pass that XYZ location into the following function. The idea was to generate a lookAt vector with GLKMatrix4MakeLookAt and define the end Quaternion for the slerp step from the lookAt matrix.
- (void)rotateToLocationX:(float)x andY:(float)y andZ:(float)z {
// Turn on the interpolation for smooth rotation
_slerping = YES; // Begin auto rotating to this location
_slerpCur = 0;
_slerpMax = 1.0;
_slerpStart = _quat;
// The eye location is defined by the look at location multiplied by this modifier
float modifier = 1.0;
// Create a look at vector for which we will create a GLK4Matrix from
float xEye = x;
float yEye = y;
float zEye = z;
//NSLog(#"%f %f %f %f %f %f",xEye, yEye, zEye, x, y, z);
_currentSatelliteLocation = GLKMatrix4MakeLookAt(xEye, yEye, zEye, 0, 0, 0, 0, 1, 0);
_currentSatelliteLocation = GLKMatrix4Multiply(_currentSatelliteLocation,self.effect.transform.modelviewMatrix);
// Turn our 4x4 matrix into a quat and use it to mark the end point of our interpolation
//_currentSatelliteLocation = GLKMatrix4Translate(_currentSatelliteLocation, 0.0f, 0.0f, GLOBAL_EARTH_Z_LOCATION);
_slerpEnd = GLKQuaternionMakeWithMatrix4(_currentSatelliteLocation);
// Print info on the quat
GLKVector3 vec = GLKQuaternionAxis(_slerpEnd);
float angle = GLKQuaternionAngle(_slerpEnd);
//NSLog(#"%f %f %f %f",vec.x,vec.y,vec.z,angle);
NSLog(#"Quat end:");
[self printMatrix:_currentSatelliteLocation];
//[self printMatrix:self.effect.transform.modelviewMatrix];
}
The interpolation works, I get a smooth rotation, however the ending location is never the XYZ I input - I know this because my globe is a sphere and I am calculating XYZ from Lat Lon. I want to look directly down the 'lookAt' vector toward the center of the earth from that lat/lon location on the surface of the globe after the rotation. I think it may have something to do with the up vector but I've tried everything that made sense.
What am I doing wrong - How can I define a final quaternion that when I finish rotating, looks down a vector to the XYZ on the surface of the globe? Thanks!
Is the following your meaning:
Your globe center is (0, 0, 0), radius is R, the start position is (0, 0, R), your final position is (0, R, 0), so rotate the globe 90 degrees around X-asix?
If so, just set lookat function eye position to your final position, the look at parameters to the globe center.
m_target.x = 0.0f;
m_target.y = 0.0f;
m_target.z = 1.0f;
m_right.x = 1.0f;
m_right.y = 0.0f;
m_right.z = 0.0f;
m_up.x = 0.0f;
m_up.y = 1.0f;
m_up.z = 0.0f;
void CCamera::RotateX( float amount )
{
Point3D target = m_target;
Point3D up = m_up;
amount = amount / 180 * PI;
m_target.x = (cos(PI / 2 - amount) * up.x) + (cos(amount) * target.x);
m_target.y = (cos(PI / 2 - amount) * up.y) + (cos(amount) * target.y);
m_target.z = (cos(PI / 2 - amount) * up.z) + (cos(amount) * target.z);
m_up.x = (cos(amount) * up.x) + (cos(PI / 2 + amount) * target.x);
m_up.y = (cos(amount) * up.y) + (cos(PI / 2 + amount) * target.y);
m_up.z = (cos(amount) * up.z) + (cos(PI / 2 + amount) * target.z);
Normalize(m_target);
Normalize(m_up);
}
void CCamera::RotateY( float amount )
{
Point3D target = m_target;
Point3D right = m_right;
amount = amount / 180 * PI;
m_target.x = (cos(PI / 2 + amount) * right.x) + (cos(amount) * target.x);
m_target.y = (cos(PI / 2 + amount) * right.y) + (cos(amount) * target.y);
m_target.z = (cos(PI / 2 + amount) * right.z) + (cos(amount) * target.z);
m_right.x = (cos(amount) * right.x) + (cos(PI / 2 - amount) * target.x);
m_right.y = (cos(amount) * right.y) + (cos(PI / 2 - amount) * target.y);
m_right.z = (cos(amount) * right.z) + (cos(PI / 2 - amount) * target.z);
Normalize(m_target);
Normalize(m_right);
}
void CCamera::RotateZ( float amount )
{
Point3D right = m_right;
Point3D up = m_up;
amount = amount / 180 * PI;
m_up.x = (cos(amount) * up.x) + (cos(PI / 2 - amount) * right.x);
m_up.y = (cos(amount) * up.y) + (cos(PI / 2 - amount) * right.y);
m_up.z = (cos(amount) * up.z) + (cos(PI / 2 - amount) * right.z);
m_right.x = (cos(PI / 2 + amount) * up.x) + (cos(amount) * right.x);
m_right.y = (cos(PI / 2 + amount) * up.y) + (cos(amount) * right.y);
m_right.z = (cos(PI / 2 + amount) * up.z) + (cos(amount) * right.z);
Normalize(m_right);
Normalize(m_up);
}
void CCamera::Normalize( Point3D &p )
{
float length = sqrt(p.x * p.x + p.y * p.y + p.z * p.z);
if (1 == length || 0 == length)
{
return;
}
float scaleFactor = 1.0 / length;
p.x *= scaleFactor;
p.y *= scaleFactor;
p.z *= scaleFactor;
}
The answer to this question is a combination of the following rotateTo function and a change to the code from Ray's tutorial at ( http://www.raywenderlich.com/12667/how-to-rotate-a-3d-object-using-touches-with-opengl ). As one of the comments on that article says there is an arbitrary factor of 2.0 being multiplied in GLKQuaternion Q_rot = GLKQuaternionMakeWithAngleAndVector3Axis(angle * 2.0, axis);. Remove that "2" and use the following function to create the _slerpEnd - after that the globe will rotate smoothly to XYZ specified.
// Rotate the globe using Slerp interpolation to an XYZ coordinate
- (void)rotateToLocationX:(float)x andY:(float)y andZ:(float)z {
// Turn on the interpolation for smooth rotation
_slerping = YES; // Begin auto rotating to this location
_slerpCur = 0;
_slerpMax = 1.0;
_slerpStart = _quat;
// Create a look at vector for which we will create a GLK4Matrix from
float xEye = x;
float yEye = y;
float zEye = z;
_currentSatelliteLocation = GLKMatrix4MakeLookAt(xEye, yEye, zEye, 0, 0, 0, 0, 1, 0);
// Turn our 4x4 matrix into a quat and use it to mark the end point of our interpolation
_slerpEnd = GLKQuaternionMakeWithMatrix4(_currentSatelliteLocation);
}
I have a problem regarding positioning an image according to the touches location, however limited to a circle.
It works for the most part, but if the angle (from the touches location to the desired location) is less than 0, it positions the image on the wrong side of the circle.
Perhaps it's some maths that I've done wrong.
Anyway, here's the code:
float newHeight, newWidth, centerPointX, centerPointY;
newHeight = -(invertedY.y - (view.frame.origin.y+view.frame.size.height/2));
newWidth = -(invertedY.x - (view.frame.origin.x+view.frame.size.width/2));
float tangent = newHeight/newWidth;
float calculatedAngle = atanf(tangent);
float s, c, d, fX, fY;
d = view.frame.size.width/2+30;
if (calculatedAngle < 0) {
s = sinf(calculatedAngle) * d;
c = cosf(calculatedAngle) * d;
} else {
s = -sinf(calculatedAngle) * d;
c = -cosf(calculatedAngle) * d;
}
fX = view.center.x + c;
fY = view.center.y + s;
[delegate setPoint:CGPointMake(fX, fY)];
NSLog(#"angle = %.2f", calculatedAngle);
Any help appreciated.
I think the best way to limit location to a circle is calculate vector from center to touch location. Calculate vector length then divide it by that length so it would be normalized. Then multiply normalized vector by radius of circle and finally add this vector to the center to compute new location.
CGPoint touch, center;
CGPoint vector = CGPointMake(touch.x-center.x, touch.y-center.y);
float length = sqrtf(vector.x*vector.x + vector.y*vector.y);
// Normalize and multiply by radius (r)
vector.x = r * vector.x / length;
vector.y = r * vector.y / length;
[delegate setPoint:CGPointMake(center.x + vector.x, center.y + vector.y)];
I'm trying to make physics bodies generated at a random position with a random velocity hit a target. I gleaned and slightly modified this code from the web that was using chipmunk to run in Box2d
+ (CGPoint) calculateShotForTarget:(CGPoint)target from:(CGPoint) launchPos with:(float) velocity
{
float xp = target.x - launchPos.x;
float y = target.y - launchPos.y;
float g = 20;
float v = velocity;
float angle1, angle2;
float tmp = pow(v, 4) - g * (g * pow(xp, 2) + 2 * y * pow(v, 2));
if(tmp < 0){
NSLog(#"No Firing Solution");
}else{
angle1 = atan2(pow(v, 2) + sqrt(tmp), g * xp);
angle2 = atan2(pow(v, 2) - sqrt(tmp), g * xp);
}
CGPoint direction = CGPointMake(cosf(angle1),sinf(angle1));
CGPoint force = CGPointMake(direction.x * v, direction.y * v);
NSLog(#"force = %#", NSStringFromCGPoint(force));
NSLog(#"direction = %#", NSStringFromCGPoint(direction));
return force;
}
The problem is I don't know how to apply this to my program, I have a gravity of -20 for y but putting 20 for g and a lower velocity like 10 for v gets me nothing but "No Firing Solution".
What am I doing wrong?
A lower velocity of 10 is never going to work the projectile doesn't have enough power to travel the distance.
The error in the calculation is that everything is in meters except for the distance calculations which are in pixels!
Changing the code to this fixed the crazy velocities i was getting:
+ (CGPoint) calculateShotForTarget:(CGPoint)target from:(CGPoint) launchPos with:(float) velocity
{
float xp = (target.x - launchPos.x) / PTM_RATIO;
float y = (target.y - launchPos.y) / PTM_RATIO;
float g = 20;
float v = velocity;
float angle1, angle2;
float tmp = pow(v, 4) - g * (g * pow(xp, 2) + 2 * y * pow(v, 2));
if(tmp < 0){
NSLog(#"No Firing Solution");
}else{
angle1 = atan2(pow(v, 2) + sqrt(tmp), g * xp);
angle2 = atan2(pow(v, 2) - sqrt(tmp), g * xp);
}
CGPoint direction = CGPointMake(cosf(angle1),sinf(angle1));
CGPoint force = CGPointMake(direction.x * v, direction.y * v);
NSLog(#"force = %#", NSStringFromCGPoint(force));
NSLog(#"direction = %#", NSStringFromCGPoint(direction));
return force;
}
I need to rotate an image by very small angle, like 1-5 degrees. Does OpenCV provide simple way of doing that? From reading docs i can assume that getAffineTransform() should be involved, but there is no direct example of doing something like:
IplImage *rotateImage( IplImage *source, double angle);
If you use OpenCV > 2.0 it is as easy as
using namespace cv;
Mat rotateImage(const Mat& source, double angle)
{
Point2f src_center(source.cols/2.0F, source.rows/2.0F);
Mat rot_mat = getRotationMatrix2D(src_center, angle, 1.0);
Mat dst;
warpAffine(source, dst, rot_mat, source.size());
return dst;
}
Note: angle is in degrees, not radians.
See the C++ interface documentation for more details and adapt as you need:
getRotationMatrix
warpAffine
Edit: To down voter: Please comment the reason for down voting a tried and tested code?
#include "cv.h"
#include "highgui.h"
#include "math.h"
int main( int argc, char** argv )
{
IplImage* src = cvLoadImage("lena.jpg", 1);
IplImage* dst = cvCloneImage( src );
int delta = 1;
int angle = 0;
int opt = 1; // 1： rotate & zoom
// 0: rotate only
double factor;
cvNamedWindow("src", 1);
cvShowImage("src", src);
for(;;)
{
float m[6];
CvMat M = cvMat(2, 3, CV_32F, m);
int w = src->width;
int h = src->height;
if(opt)
factor = (cos(angle*CV_PI/180.) + 1.05) * 2;
else
factor = 1;
m[0] = (float)(factor*cos(-angle*2*CV_PI/180.));
m[1] = (float)(factor*sin(-angle*2*CV_PI/180.));
m[3] = -m[1];
m[4] = m[0];
m[2] = w*0.5f;
m[5] = h*0.5f;
cvGetQuadrangleSubPix( src, dst, &M);
cvNamedWindow("dst", 1);
cvShowImage("dst", dst);
if( cvWaitKey(1) == 27 )
break;
angle =(int)(angle + delta) % 360;
}
return 0;
}
UPDATE: See the following code for rotation using warpaffine
https://code.google.com/p/opencvjp-sample/source/browse/trunk/cpp/affine2_cpp.cpp?r=48
#include <cv.h>
#include <highgui.h>
using namespace cv;
int
main(int argc, char **argv)
{
// (1)load a specified file as a 3-channel color image,
// set its ROI, and allocate a destination image
const string imagename = argc > 1 ? argv[1] : "../image/building.png";
Mat src_img = imread(imagename);
if(!src_img.data)
return -1;
Mat dst_img = src_img.clone();
// (2)set ROI
Rect roi_rect(cvRound(src_img.cols*0.25), cvRound(src_img.rows*0.25), cvRound(src_img.cols*0.5), cvRound(src_img.rows*0.5));
Mat src_roi(src_img, roi_rect);
Mat dst_roi(dst_img, roi_rect);
// (2)With specified three parameters (angle, rotation center, scale)
// calculate an affine transformation matrix by cv2DRotationMatrix
double angle = -45.0, scale = 1.0;
Point2d center(src_roi.cols*0.5, src_roi.rows*0.5);
const Mat affine_matrix = getRotationMatrix2D( center, angle, scale );
// (3)rotate the image by warpAffine taking the affine matrix
warpAffine(src_roi, dst_roi, affine_matrix, dst_roi.size(), INTER_LINEAR, BORDER_CONSTANT, Scalar::all(255));
// (4)show source and destination images with a rectangle indicating ROI
rectangle(src_img, roi_rect.tl(), roi_rect.br(), Scalar(255,0,255), 2);
namedWindow("src", CV_WINDOW_AUTOSIZE);
namedWindow("dst", CV_WINDOW_AUTOSIZE);
imshow("src", src_img);
imshow("dst", dst_img);
waitKey(0);
return 0;
}
Check my answer to a similar problem:
Rotating an image in C/C++
Essentially, use cvWarpAffine - I've described how to get the 2x3 transformation matrix from the angle in my previous answer.
Updating full answer for OpenCV 2.4 and up
// ROTATE p by R
/**
* Rotate p according to rotation matrix (from getRotationMatrix2D()) R
* #param R Rotation matrix from getRotationMatrix2D()
* #param p Point2f to rotate
* #return Returns rotated coordinates in a Point2f
*/
Point2f rotPoint(const Mat &R, const Point2f &p)
{
Point2f rp;
rp.x = (float)(R.at<double>(0,0)*p.x + R.at<double>(0,1)*p.y + R.at<double>(0,2));
rp.y = (float)(R.at<double>(1,0)*p.x + R.at<double>(1,1)*p.y + R.at<double>(1,2));
return rp;
}
//COMPUTE THE SIZE NEEDED TO LOSSLESSLY STORE A ROTATED IMAGE
/**
* Return the size needed to contain bounding box bb when rotated by R
* #param R Rotation matrix from getRotationMatrix2D()
* #param bb bounding box rectangle to be rotated by R
* #return Size of image(width,height) that will compleley contain bb when rotated by R
*/
Size rotatedImageBB(const Mat &R, const Rect &bb)
{
//Rotate the rectangle coordinates
vector<Point2f> rp;
rp.push_back(rotPoint(R,Point2f(bb.x,bb.y)));
rp.push_back(rotPoint(R,Point2f(bb.x + bb.width,bb.y)));
rp.push_back(rotPoint(R,Point2f(bb.x + bb.width,bb.y+bb.height)));
rp.push_back(rotPoint(R,Point2f(bb.x,bb.y+bb.height)));
//Find float bounding box r
float x = rp[0].x;
float y = rp[0].y;
float left = x, right = x, up = y, down = y;
for(int i = 1; i<4; ++i)
{
x = rp[i].x;
y = rp[i].y;
if(left > x) left = x;
if(right < x) right = x;
if(up > y) up = y;
if(down < y) down = y;
}
int w = (int)(right - left + 0.5);
int h = (int)(down - up + 0.5);
return Size(w,h);
}
/**
* Rotate region "fromroi" in image "fromI" a total of "angle" degrees and put it in "toI" if toI exists.
* If toI doesn't exist, create it such that it will hold the entire rotated region. Return toI, rotated imge
* This will put the rotated fromroi piece of fromI into the toI image
*
* #param fromI Input image to be rotated
* #param toI Output image if provided, (else if &toI = 0, it will create a Mat fill it with the rotated image roi, and return it).
* #param fromroi roi region in fromI to be rotated.
* #param angle Angle in degrees to rotate
* #return Rotated image (you can ignore if you passed in toI
*/
Mat rotateImage(const Mat &fromI, Mat *toI, const Rect &fromroi, double angle)
{
//CHECK STUFF
// you should protect against bad parameters here ... omitted ...
//MAKE OR GET THE "toI" MATRIX
Point2f cx((float)fromroi.x + (float)fromroi.width/2.0,fromroi.y +
(float)fromroi.height/2.0);
Mat R = getRotationMatrix2D(cx,angle,1);
Mat rotI;
if(toI)
rotI = *toI;
else
{
Size rs = rotatedImageBB(R, fromroi);
rotI.create(rs,fromI.type());
}
//ADJUST FOR SHIFTS
double wdiff = (double)((cx.x - rotI.cols/2.0));
double hdiff = (double)((cx.y - rotI.rows/2.0));
R.at<double>(0,2) -= wdiff; //Adjust the rotation point to the middle of the dst image
R.at<double>(1,2) -= hdiff;
//ROTATE
warpAffine(fromI, rotI, R, rotI.size(), INTER_CUBIC, BORDER_CONSTANT, Scalar::all(0));
//& OUT
return(rotI);
}
IplImage* rotate(double angle, float centreX, float centreY, IplImage* src, bool crop)
{
int w=src->width;
int h=src->height;
CvPoint2D32f centre;
centre.x = centreX;
centre.y = centreY;
CvMat* warp_mat = cvCreateMat(2, 3, CV_32FC1);
cv2DRotationMatrix(centre, angle, 1.0, warp_mat);
double m11= cvmGet(warp_mat,0,0);
double m12= cvmGet(warp_mat,0,1);
double m13= cvmGet(warp_mat,0,2);
double m21= cvmGet(warp_mat,1,0);
double m22= cvmGet(warp_mat,1,1);
double m23= cvmGet(warp_mat,1,2);
double m31= 0;
double m32= 0;
double m33= 1;
double x=0;
double y=0;
double u0= (m11*x + m12*y + m13)/(m31*x + m32*y + m33);
double v0= (m21*x + m22*y + m23)/(m31*x + m32*y + m33);
x=w;
y=0;
double u1= (m11*x + m12*y + m13)/(m31*x + m32*y + m33);
double v1= (m21*x + m22*y + m23)/(m31*x + m32*y + m33);
x=0;
y=h;
double u2= (m11*x + m12*y + m13)/(m31*x + m32*y + m33);
double v2= (m21*x + m22*y + m23)/(m31*x + m32*y + m33);
x=w;
y=h;
double u3= (m11*x + m12*y + m13)/(m31*x + m32*y + m33);
double v3= (m21*x + m22*y + m23)/(m31*x + m32*y + m33);
int left= MAX(MAX(u0,u2),0);
int right= MIN(MIN(u1,u3),w);
int top= MAX(MAX(v0,v1),0);
int bottom= MIN(MIN(v2,v3),h);
ASSERT(left<right&&top<bottom); // throw message?
if (left<right&&top<bottom)
{
IplImage* dst= cvCreateImage( cvGetSize(src), IPL_DEPTH_8U, src->nChannels);
cvWarpAffine(src, dst, warp_mat/*, CV_INTER_LINEAR + CV_WARP_FILL_OUTLIERS, cvScalarAll(0)*/);
if (crop) // crop and resize to initial size
{
IplImage* dst_crop= cvCreateImage(cvSize(right-left, bottom-top), IPL_DEPTH_8U, src->nChannels);
cvSetImageROI(dst,cvRect(left,top,right-left,bottom-top));
cvCopy(dst,dst_crop);
cvReleaseImage(&dst);
cvReleaseMat(&warp_mat);
//ver1
//return dst_crop;
// ver2 resize
IplImage* out= cvCreateImage(cvSize(w, h), IPL_DEPTH_8U, src->nChannels);
cvResize(dst_crop,out);
cvReleaseImage(&dst_crop);
return out;
}
else
{
/*cvLine( dst, cvPoint(left,top),cvPoint(left, bottom), cvScalar(0, 0, 255, 0) ,1,CV_AA);
cvLine( dst, cvPoint(right,top),cvPoint(right, bottom), cvScalar(0, 0, 255, 0) ,1,CV_AA);
cvLine( dst, cvPoint(left,top),cvPoint(right, top), cvScalar(0, 0, 255, 0) ,1,CV_AA);
cvLine( dst, cvPoint(left,bottom),cvPoint(right, bottom), cvScalar(0, 0, 255, 0) ,1,CV_AA);*/
cvReleaseMat(&warp_mat);
return dst;
}
}
else
{
return NULL; //assert?
}
}