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Questions tagged [alpha]

An alpha channel determines the transparency of an image or view. Lower values are more transparent, and higher values are more opaque

An alpha channel determines the transparency of an image or view. Lower values are more transparent, and higher values are more opaque

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Sprite visibility problems after using low values of alpha

The plan was very simple: Using MouseEvent.CLICK to hide/show a Sprite. The first click should make it disappear, the second make it visible again. What actually happened was really odd, as the Sprite didn't become visible when alpha was set to 1…
user5081001
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Sprite transparency sorting error in three.js

I've just downloaded the latest Three.js master "mrdoob-three.js-d6384d2" , I've modified the "webgl_nearestneighbour.html" to show a transparent image and this is the result: http://i.share.pho.to/8cccac74_l.jpeg I can't understand if it's by…
Techno.Shaman
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Why different lines drawn using cv::line function has different transparency (alpha) levels?

I used houghLines transformation to detect lines in an image and I draw the lines detected by that on a separate Mat image using cv::line() function. Note that the lines detected by houghLinesP are usually overlapping with each other and high in…
Samitha Chathuranga
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Making a UIBarButtonItem transparent in swift

How do I make a UIBarButtonItem's alpha be 0 in swift? I want it to fade in when a specific element appears on the screen. Does anybody know how to do this? Or any equally effective method would be great.
Matt Spoon
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How to deal with etc1 alpha channel

I'm trying to support ETC1 for my android game but I have no idea how to deal with the alpha channel. Can anyone tell me where to start and how to get ETC1 working with alpha? Update: Using: gl_fragColor = vec4(tex1.rgb,tex2.a); doesn't work, there…
jeromintus
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Animation of setAlpha for UILabel not working

I have some UILabels on a view that I want to fade when the someone is holding down on the view. I am trying to perform the fade by changing the alpha value of the text from 1.0 to 0.5 and then back again when the touch is released. Here is my…
myles
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How can I put a device-independent bitmap into the Windows clipboard using just direct WinAPI? (No MFC or other wrappers)

I've been trying to get this to work for awhile now, but I can't seem to figure it out, and hours of Googling has yet to reveal any useful results. I have an array of 32-bit pixels in RGBA order, and I want to create a device-independent bitmap from…
celticminstrel
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png uncompressed by CGContextDrawImage is different from orign png image in xcode

I have a png image which color is white, but alpha channel is different.That is a pixel of the image is made of (255, 255, 255, x),x belongs to [0~255]. I use the following code to read it into menory, find color value changed to the same as alpha…
jayzhen
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how to infer alpha value from pair of opaque images

I have two images, one with a white background, and one with a black background, I want to convert these images into one semi transparent image I have found that color*alpha=blackBackgroundImage color*alpha+(1-alpha)=whiteBackgroundImage I want a…
william malo
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Sequence Action With EnumerateChildNodeWithName

I want two different types of nodes to fade there alpha to 0 one after the other (with a sequence). However to find the nodes to fade, I'm using EnumerateChildNodeWithName and there is two of them, so I'm unable (I think) to use a sequence because I…
Jarron
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javascript strokeRect opacity not setting to 1

I am trying to draw then erase rectangles on a gray canvas. I draw in red, then erase by drawing in gray. This works perfectly for fillRect() but not for strokeRect(). In the latter case, it acts like the opacity/alpha is not 1.0. This problem…
GFurnas
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OpenGL ES 2.0 Alpha

I am trying to load a texture PNG ( exported by photoshop) and use it in OpenGL ES 2.0 in Android, but the solid color seems like transparent ( black circle in the png is totally black) I has been read that if you scale a png more than 50% that bug…
D4rWiNS
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UIView is not responding when changed in NSTimer method

I have this NSTimer repeating loop that will check if there is any news in my app. The checking part is irrelevant and it works fine, but to show if there's news or not, I made a UIView called orangeDot. This should be orangeDot.alpha = 1.0 if there…
Simon Degn
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PNG composition using GD and PHP

I am trying to take a rectangular png and add depth using GD by duplicating the background and moving it down 1 pixel and right 1 pixel. I am trying to preserve a transparent background as well. I am having a bunch of trouble with preserving the…
Dominic
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Using Bitmap as alpha map of a cone

I'm wondering if i can use a bitmap to set alpha channel of a cone in wpf 3d : Black = > alpha = 0 % white => alpha = 100 % (more probably 80 % to see inside alpha difference ...) alt text http://www.visualdmx.fr/bitmap_alpha.png
guillaume
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