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I need to replicate the effect that the UIButton does on an image when tapped, the highlighting. See: The original PNG is a square with alpha background. When I set it as UIButton's image it automatically apply an effect on the non-alpha pixels of the image. How to do this effect? You could achieve this with a simple category on UIImage: @interface UIImage (Tint) - (UIImage *)tintedImageUsingColor:(UIColor *)tintColor; @end @implementation UIImage (Tint) - (UIImage *)tintedImageUsingColor:(UIColor *)tintColor { UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale); CGRect drawRect

百度百科 OSI（Open System Interconnect），即开放式系统互联。 一般都叫OSI参考模型，是ISO组织在1985年研究的网络互联模型。该体系结构标准定义了网络互联的七层框架（物理层、数据链路层、网络层、传输层、会话层、表示层和应用层）。 TCP/IP是一组用于实现网络互连的通信协议。Internet网络体系结构以TCP/IP为核心。基于TCP/IP的参考模型将协议分成四个层次，它们分别是：网络访问层、网际互联层（主机到主机）、传输层、和应用层。 OSI参考模型与TCP/IP模型对比 层次结构 相同之处：都采用了分层体系结构；不同之处：TCP/IP参考模型比OSI参考模型更简化。 层次关系 相同之处：都是对等的层间通信；不同之处：TCP/IP参考模型比OSI参考模型层次更清晰简练。 功能 在功能上，大致相同，在两个模型中，传输层及以上的各层都是为了通信的进程提供点到点、与网络无关的传输服务；TCP/IP参考模型比OSI参考模型有更好的网络管理功能。 数据传输原理 把TCP/IP模型的数据传输原理分成几个步骤： (1) 当应用进程A的数据传送到应用层时，应用层为数据加上本层的控制报头后，将其组织成应用层的数据服务单元，然后向下传输到传输层。 (2) 传输层收到该数据单元后，加上本层的控制报头，构成传输层的数据服务单元，该数据服务单元被称为报文(message)。

Hello this weekend I started to watch the 2011 WWDC videos. I've found really interesting topics about iOS. My favorites were about performance and graphics, but I've found two of them apparently in contradiction. Of course there is something that I didn't get. The sessions that I'm talking about are Understanding UIKit Rendering -121 and Polishing your app -105. Unfortunately sample code from 2011 is still not downloadable, so is pretty hard to have an overall view. In one session they explain that most of times offscreen rendering should be avoided during visualization in scrollview etc.

I'm trying to load in TEST phase a network configuration which has a memory data layer first and then a convolution layer. The MemoryData layer creation succeeds, But the convolution layer's creation fails at the following location: LOG(INFO) << "Creating layer " << param.name(); const string& type = param.type(); CreatorRegistry& registry = Registry(); CHECK_EQ(registry.count(type), 1) << "Unknown layer type: " << type << " (known types: " << LayerTypeList() << ")"; Printed error is: F0519 14:54:12.494139 14504 layer_factory.hpp:77] Check failed: registry.count(t ype) == 1 (0 vs. 1) Unknown

How to create gradient colour look like following image programatically. When you say "apply it over the image as a gradient", do you mean as a mask (revealing the image at the top, having it fade the image to transparent at the bottom)? If that's the case, you can apply that gradient as a mask, using CAGradientLayer : CAGradientLayer *gradientMask = [CAGradientLayer layer]; gradientMask.frame = self.imageView.bounds; gradientMask.colors = @[(id)[UIColor whiteColor].CGColor, (id)[UIColor clearColor].CGColor]; self.imageView.layer.mask = gradientMask; The above does a simple vertical gradient

Suppose I run the following script: import matplotlib.pyplot as plt lineWidth = 20 plt.figure() plt.plot([0,0],[-1,1], lw=lineWidth, c='b') plt.plot([-1,1],[-1,1], lw=lineWidth, c='r') plt.plot([-1,1],[1,-1], lw=lineWidth, c='g') plt.show() This produces the following: How can I specify the top-to-bottom order of the layers instead of having Python pick for me? I don't know why zorder has that behavior and it's likely that might be a bug or, at the very least, a badly documented feature. It might be because there are already automatic references to zorder when you build a plot (like grid, axis