cgaffinetransform

问题 I have a tableView where when a user taps on that cell, I want the cell to expand and fill the entire screen with that color. Currently, it does scale to fill the entire screen but the cells above it will also show. The colors come from an API and each cell changes color when the user taps the "Generate" button. Due to how the API's JSON file is structured, I only want 5 colors on the screen at a time. I can't figure out why the cells above it don't move upwards or how I can move the clicked

问题 I have read about affine transform in wikipedia this page: https://en.wikipedia.org/wiki/Affine_transformation I says that if I would like to reflect an image, I can set the affine matrix to be [[-1, 0, 0], [0, 1, 0], [0, 0, 1]], but when I tried this code: im = cv2.imread(imgpth) im = cv2.resize(im, (1024, 512)) H, W, _ = im.shape cv2.imshow('org', im) M = np.float32([[-1, 0, 0], [0, 1, 0]]) aff = cv2.warpAffine(im, M, (W, H)) cv2.imshow('affine', aff) cv2.waitKey(0) I did not an flipped

问题 I have read about affine transform in wikipedia this page: https://en.wikipedia.org/wiki/Affine_transformation I says that if I would like to reflect an image, I can set the affine matrix to be [[-1, 0, 0], [0, 1, 0], [0, 0, 1]], but when I tried this code: im = cv2.imread(imgpth) im = cv2.resize(im, (1024, 512)) H, W, _ = im.shape cv2.imshow('org', im) M = np.float32([[-1, 0, 0], [0, 1, 0]]) aff = cv2.warpAffine(im, M, (W, H)) cv2.imshow('affine', aff) cv2.waitKey(0) I did not an flipped

问题 I have read about affine transform in wikipedia this page: https://en.wikipedia.org/wiki/Affine_transformation I says that if I would like to reflect an image, I can set the affine matrix to be [[-1, 0, 0], [0, 1, 0], [0, 0, 1]], but when I tried this code: im = cv2.imread(imgpth) im = cv2.resize(im, (1024, 512)) H, W, _ = im.shape cv2.imshow('org', im) M = np.float32([[-1, 0, 0], [0, 1, 0]]) aff = cv2.warpAffine(im, M, (W, H)) cv2.imshow('affine', aff) cv2.waitKey(0) I did not an flipped

问题 How can I rotate an image drawn by CGContextDrawImage() at its center? In drawRect: CGContextSaveGState(c); rect = CGRectOffset(rect, -rect.size.width / 2, -rect.size.height / 2); CGContextRotateCTM(c, angle); CGContextDrawImage(c, rect, doodad.CGImage); CGContextRotateCTM(c, -angle); CGContextTranslateCTM(c, pt.x, pt.y); prevRect = rect; CGContextRestoreGState(c); I draw the image at the origin, and rotate it at its center, then translate to where it should be drawn. Not working. 回答1: The

问题 I'd like to take an affine matrix that I have from OpenCV: Mat T = getAffineTransform(src_pt, dst_pt); and then convert it into a CGAffineTransform for use in Core Graphics/Objective-C/iOS. (CGAffineTransform docs) I've tried: CGAffineTransform t = CGAffineTransformIdentity; t.a = T.at<float>(0,0); t.b = T.at<float>(0,1); t.c = T.at<float>(1,0); t.d = T.at<float>(1,1); t.tx = T.at<float>(0,2); t.ty = T.at<float>(1,2); This works fine for x and y translations, but NOT if there is any rotation

问题 I am stuck with a strange problem that, I have a image view which has to shown at some angle approx 5 degree.For that I rotate my UIImageView to 5 degree but the image in UIImageView not coming proper as it was before transformation. For more understanding see images You can see the second image is looking like clipped from corners and looks some blur also. My code for rotation:- myimageView.transform = CGAffineTransformMakeRotation(radians(5)); Please suggest me how to solve this problem.

问题 I rotate my view with CGAffineTransform [view setTransform:newTransform]; The frame values remain the same after transform is applied but how do I find "rotated" or transformed values of this frame? (source: informit.com) I want the exact coordinates of rotated frame edges, that is a, b, c, d points. 回答1: One thing to keep in mind is that the transform changes the coordinate system, so you will need to be able to convert between the parent 'view' and the child (transformed) view. Also,

问题 My code needs some help from professional xcoders :-) I have a draggable uitextview called "headline" that is a subview in "mainstage". I also added a pinch gesture to change the fontsize inside the uitextview. Everything works fine but the last essential feature that I really need is the rotation of the uitextview. So I added a uislider for rotation and volia! it also works. But after this transformation the uitextview goes crazy* when it becomes a new size via the pinch gesture. (*The

问题 I found a similar question about getting just the rotation, but as I understand scaling and rotating work different in the transform matrix. Matrixes are not my strength, so if anybody would hint me how to get only the scaling out of a CGAffineTransform I'd greatly appreciate. btw. I tried applying the CGAffineTransform on a CGSize and then get the height x width to see how much it scaled, but height x width have strange values (depending on the rotation found in the CGAffineTransform, so ...