alpha

does OpenCV support alpha-channel? Or is there any way to work with transparent png? I need to merge two images, where the first one is background and the second one is image which was rotated by cvWarpAffine. I can do this by merging pixels one by one and omit pixels with some value, which I set in cvScalar in cvWarpAffine. However, I don't think that this is intended solution. Thanks for suggestions Updated answer: Use CV_LOAD_IMAGE_UNCHANGED flag to load all four channels (including Alpha) from the image. Then, use mixChannels() and/or split() to separate the alpha channel from others, and

I'm having some major issues getting PNG transparency on a PNG that is being rotated. $filename = 'bird_up.png'; $source = imagecreatefrompng($filename) or die('Error opening file '.$filename); imagealphablending($source, false); imagesavealpha($source, true); $rotation = imagerotate($source, $degrees, imageColorAllocateAlpha($source, 0, 0, 0, 127)); imagealphablending($source, false); imagesavealpha($source, true); header('Content-type: image/png'); imagepng($rotation); imagedestroy($source); imagedestroy($rotation); I've added a working commented version below <?php // this file writes the

第一种方式，直接写代码 mainactivity代码： package com.glsite.tweenanim; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.view.animation.AlphaAnimation; import android.view.animation.Animation; import android.view.animation.AnimationSet; import android.view.animation.RotateAnimation; import android.view.animation.ScaleAnimation; import android.view.animation.TranslateAnimation; import android.widget.ImageView; public class MainActivity extends AppCompatActivity { private ImageView mIv; @Override protected void onCreate(Bundle

I have a MapView and I want to display a black semi transparent rectangle on top with a text inside. Not over the entire map only on section of it (maybe on the top corner) just as an info box (like the one in the iPod player that appears on double tap and displays the Mute and skip buttons). I tried google but I'm not getting any clear answers. How is the best way to accomplish this? Thanks in advance Can be easily done with interface builder: View Hierarchy NOTE The background has to be a separate view which is the first entry in the list of controls, so it is in the background. Setting the

I would like to make a JPEG image file with some pixels that are partially transparent or fully transparent, similar to a PNG file with an alpha channel. Is this possible? If so, how would I go about doing this? I would like to use the image on a website. If I try to do this, would it work in any or all of the popular browsers (IE 7+, Firefox, Safari)? Assuming it is possible, will it just work, or are there any tricks or hacks required to make it work? EDIT: Some of the replies say I can't do this. However, I found this page describing a JPEG image with transparency. Does anyone know if there

I have been looking for a solution to my problem. But my code seems to be ok. I'll try to explain: I have a TextView with android:alpha="0" in my layout definition. I want (when a image is clicked) show that TextView with an AlphaAnimation, from 0.0f to 1.0f. My problem is that when I click the image, nothing happens. But the strange thing, is that if I set it's alpha to 1 in the layout definition, and I click the image, I can see the animation (alpha 1 -> alpha 0 -> alpha 1). What am I doing wrong? My code: TextView tv = (TextView) findViewById(R.id.number); AlphaAnimation animation1 = new

无穷小 定义 如果函数 f ( x ) f(x) f ( x ) 当 x → x 0 x \rightarrow x_0 x → x 0 ​ (或 x → ∞ x \rightarrow \infty x → ∞ )时的极限为零，那么称函数 f ( x ) f(x) f ( x ) 为当 x → x 0 x \rightarrow x_0 x → x 0 ​ (或 x → ∞ x \rightarrow \infty x → ∞ )时的无穷小。 注意： （1）无穷小不可以和很小的量混为一谈，无穷小量不是指量的大小，而是 指量的变化趋势 （以零为极限）； （2）无穷小是这样的函数：在 x → x 0 x \rightarrow x_0 x → x 0 ​ (或 x → ∞ x \rightarrow \infty x → ∞ )过程中，函数的绝对值能小于任意给定的正数 ϵ \epsilon ϵ 。而很小的数如百万分之一，就不能小于任意给定的正数 ϵ \epsilon ϵ 。例如取 ϵ \epsilon ϵ 等于千万分之一，则百万分之一就不能小于这个给定的 ϵ \epsilon ϵ 。但零是可以作为无穷小的唯一常数，因为如果 f ( x ) ≡ 0 f(x) \equiv 0 f ( x ) ≡ 0 ，那么对于任意给定的正数 ϵ \epsilon ϵ ，总有 ∣ f ( x ) ∣ <