alpha

Apple tech note QA1037 says "To create an alpha-only bitmap context simply pass NULL for the colorspace parameter." However, I am not sure what to pass for the bitmapInfo parameter. I was trying something like this, with kCGImageAlphaOnly: CGContextRef ctx = CGBitmapContextCreate(NULL, scaledSize.width, scaledSize.height, 8, scaledSize.width, NULL, kCGImageAlphaOnly); But this gives me an warning about the enum being wrong. What should I put there instead? The docs clearly state you can use values from the CGImageAlphaInfo even though the parameter is defined as needed a value from the

I have published my application in alpha testing for testing purpose. Now I want delete it permanently from listing. So, Is it possible to delete published application in alpha mode? If your app is in Alpha and no one has downloaded it. You have to unpublished your app first and then contact Google. They will delete your app for you. I had them delete 1 app for me. If you has not published your application yet you can delete it. Once you publish it you can only unpublish it. So you can delete it. You can only unpublish but cannot delete it. it will not display to user but it will be in your

The effect that I am trying to achieve is having a circle of light in an area of darkness. The effect is similar to that in pokemon games, when you are in a dark cave and only have limited vision surrounding you. From what I have tried and read, I have been unable to create a mask over nodes in sprite kit that has alpha levels. The masks I manage to create all have a hard edge, and basically just crop. Reading on the apple developer page about the SKCropNode, which has the maskNode property, it says "If the pixel in the mask has an alpha value of less than 0.05, the image pixel is masked out."

I am plotting many points using ggplot with a constant transparency value for all points. What I find is that the circular points have a more transparent fill than their individual border, so that the borders are noticeably brighter than their fill (I'm plotting light circles on a dark background), i.e. there seems to be a ringing artefact. The effect is that they look like rings rather than semi-transparent circles. library(ggplot2) set.seed(123) data <- data.frame( x = sample(1:100,2000, replace=T), y = sample(1:100,2000, replace=T) ) ggplot(data, aes(x,y)) + geom_point(alpha=0.2, color=

I have looked all over for how to correctly manage alpha when I'm resizing a png. I've managed to get it to keep transparency, but only for pixels that are completely transparent. Here's my code: $src_image = imagecreatefrompng($file_dir.$this->file_name); $dst_image = imagecreatetruecolor($this->new_image_width, $this->new_image_height); imagealphablending($dst_image, true); imagesavealpha($dst_image, true); $black = imagecolorallocate($dst_image, 0, 0, 0); imagecolortransparent($dst_image, $black); imagecopyresampled($dst_image, $src_image, 0, 0, 0, 0, $this->new_image_width, $this->new

I have been working on colour images(RGB) and color images with an alpha channel(RGBA) . Reading an alpha channel from an RGBA image is pretty easy and I can even split the 4 channels of the image. Is there any method by which I can add an alpha channel to a monochrome or a grayscale image? Also, can alpha channel be separately added to the R,G,B Channels individually ? The code I am using to read a transparent image and split the channels is as follows - import cv2 img = cv2.imread(image1_path,-1) b = img[:,:,0] g = img[:,:,1] r = img[:,:,2] a = img[:,:,3] img_merge = cv2.merge((b,g,r,a)) cv2