pixel | 易学教程

MFC中CDC的使用绘图(三)

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5．清屏 Windows没有提供专门的清屏函数，可以调用CWnd的下面两个函数调用来完成该功能： void Invalidate(BOOL bErase = TRUE); void UpdateWindow( ); 或调用CWnd的函数 BOOL RedrawWindow( LPCRECT lpRectUpdate = NULL, CRgn* prgnUpdate = NULL, UINT flags = RDW_INVALIDATE | RDW_UPDATENOW | RDW_ERASE ); 来完成。例如（菜单项ID_CLEAR的事件处理函数）： CDrawView::OnClear() { // 调用OnDraw来清屏 //Invalidate(); //UpdateWindow( ); RedrawWindow( ); } 也可以用画填充背景色矩形的方法来清屏，如： RECT rect; GetClientRect(&rect); pDC->FillSolidRect(&rect, RGB(255, 255, 255)); 6．在控件上绘图可以在对话框资源中放置图片控件，并对其类型属性选Frame。可在对话框的绘图消息响应函数OnPaint或其他函数中，用CWnd类的函数GetDlgItem： CWnd* GetDlgItem( int nID ) const;

Read HSV value of pixel in opencv

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问题 how would you go about reading the pixel value in HSV format rather than RGB? The code below reads the pixel value of the circles' centers in RGB format. Is there much difference when it comes to reading value in HSV? int main(int argc, char** argv) { //load image from directory IplImage* img = cvLoadImage("C:\\Users\\Nathan\\Desktop\\SnookerPic.png"); IplImage* gray = cvCreateImage(cvGetSize(img), IPL_DEPTH_8U, 1); CvMemStorage* storage = cvCreateMemStorage(0); //covert to grayscale

Access pixels with Mat OpenCV

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问题 I would like to access pixels in RGB with OpenCV 2.3. I'm trying like this but it's like every pixels are equal frame after frame because I got no output. Images are from my webcam and I can see them. Btw RED = 0; THX Mat frame; Mat oldFrame; VideoCapture cap(0); cap >> oldFrame; sumFramePix = oldFrame.cols * oldFrame.rows; nbChannels = oldFrame.channels(); cout << "NbcHANNELs : " << nbChannels << endl; imshow("Video 1", oldFrame); while(1) { cap >> frame; imshow("Video 1", frame); for(int i

Web Design for Smart Phone - Pixel Size

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问题 I need someone to help clarify my understanding regarding pixel size on new phones with high density screens. Since, it's throwing a curve ball into my web design. My initial understanding about smartphones was that the pixel size was roughly 480 x 320, which made designing easy, since pixels were still the same pixels. However, some smart phones are double (or more) than this. I believe the iPhone is truly double at 960 x 640. My Galaxy Nexus is 1280 x 720. Now, this works just fine when

python生成字符视频

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python生成字符视频作为一个编程小白，刚刚入门学习了python，在学习过程中，想实现一些有趣的功能，但是由于自身能力目前又想，于是参考了参考了网上的程序，实现了该功能。现将实现过程中出现的问题进行列举以及解决方法：一、实现原理将视频的一帧一帧分成图片；将图片字符化处理；再将字符化处理的图片组合成视频；二、源代码（修改.avi文件的读取路径与生成字符视频的存储路径以及读取生成字符图片的数量即可） # -*- coding: utf-8 -*- import cv2 import os from PIL import Image , ImageDraw , ImageFont WIDTH = 80 # 定义输出画面的宽度 HEIGHT = 45 # 定义 ascii_char = list ( "$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/\|()1{}[]?-_+~<>i!lI;:,\"^`'. " ) # 所用字符列表 # 将256灰度映射到70个字符上 def get_char ( r , g , b , alpha = 256 ) : # alpha透明度 if alpha == 0 : return ' ' length = len ( ascii_char ) gray = int ( 0.2126 * r + 0

iPhone OpenGL ES 2.0 - Pixel Perfect Textures

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问题 How can I get my textures to align with the screen pixels for pixel perfect graphics in OpenGL ES 2.0? This is critical for a project I'm working on which uses pixel art graphics. Any help on this would be great! 回答1: See my answer here: OpenGL Texture Coordinates in Pixel Space This has been asked a few times, but I don't have the links at hand, so a quick and rough explanation. Let's say the texture is 8 pixels wide: | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | ^ ^ ^ ^ ^ ^ ^ ^ ^ 0.0 | | | | | | | 1.0

iPhone OpenGL ES 2.0 - Pixel Perfect Textures

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iOS: Get pixel-by-pixel data from camera

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问题 I'm aware of AVFoundation and its capture support (not too familiar though). However, I don't see any readily-accessible API to get pixel-by-pixel data (RGB-per-pixel or similar). I do recall reading in the docs that this is possible, but I don't really see how. So: Can this be done? If so, how? Would I be getting raw image data, or data that's been JPEG-compressed? 回答1: AV Foundation can give you back the raw bytes for an image captured by either the video or still camera. You need to set up

Convert Pixels to Points

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问题 I have a need to convert Pixels to Points in C#. I've seen some complicated explanations about the topic, but can't seem to locate a simple formula. Let's assume a standard 96dpi, how do I calulate this conversion? 回答1: There are 72 points per inch; if it is sufficient to assume 96 pixels per inch, the formula is rather simple: points = pixels * 72 / 96 There is a way to get the configured pixels per inch of your display in Windows using GetDeviceCaps. Microsoft has a guide called "Developing

从像素之间谈起：像素游戏的画面增强

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转自：http://fushigi-hako.site/2017/07/02/from_pixel_to_screen_1/ 无所不在的像素画分类随着分辨率的普遍提高，我们已经告别了依赖于简陋像素来表现游戏画面的年代。但还是有不少人像我一样沉迷于像素美术和游戏。如今到处可以都可以看到的各式像素作品，虽然大多被直接称呼为像素画，但实际上已经分化为很多分支，简单的将其归类为像素作品未免太含糊。在开始正文之前我先将他们粗粗的分个类。一些比较常见的代表如：大颗粒像素，此类像素作品一般细节较少，人物符号化或者抽象化。同时还可能出现非像素元素，如光晕，渐变　　2.粒度较小的像素画，主要还是色块化，边缘并没有强化。　　3.强化边缘和高光，细节丰富，但是普遍尺寸较小。另外，在一些UI图标的绘制过程中，由于图标较小，也同样采用像素点绘的方式。因为它平时也不会被称为像素画，所以这里也不讨论。其中第3种是我在本文中将着重讨论的。这类像素图可能和平时所提到的像素图差的最远，因为它并不是为了做出像素化效果而诞生的。相反它是游戏机在分辨率和色板支持加强之后的产物（光是从GB到GBC，支持的色深就从2位变成了15位）。在这方面，任天堂算是是做到了极致（也可能因为任天堂的主机的屏幕天生小的缘故）这类像素画在抗锯齿（伪），光照，色彩的调和的方面很有特点（这篇文章中不细说）再现像素画就GBA而言