qpixmap

问题 I'm trying to create a QPixmap from a numpy array. The numpy array image is going to be 2D (ie no color info just grayscale). I'm trying to adapt this answer to my needs however I don't quite understand this line: b = (255 << 24 | a[:,:,0] << 16 | a[:,:,1] << 8 | a[:,:,2]).flatten() # pack RGB values There is some bitshifting going on and some bitwise or ' ing but I don't quite get it to be honest. So my dumbed down example is as follows: x, y = np.meshgrid(np.arange(1920), np.arange(1080),

问题 I'm building a music player, that checks the status with SqueezePlay, which is a SqueezeBox controller app. To cut a long story short, I'm checking the status of Squeezeplay ever 5 seconds by using threading. If the song title changes, I let it update the labels (Qlabel, album artwork (QPixmap), etc. However, when I ask it to update it via threading, I'm getting It is not safe to use pixmaps outside the GUI thread . How can I do threading but still set the QPixmap? Sample code: #self.sq

问题 I am developing a graphics application using Qt 4.5 and am putting images in the QPixmapCache, I wanted to optimise this so that if a user inserts an image which is already in the cache it will use that. Right now each image has a unique id which helps optimises itself on paint events. However I realise that if I could calculate a hash of the image I could lookup the cache to see if it already exists and use that (it would help more for duplicate objects of course). My problem is that if its

问题 I'm trying to draw an icon(.png) inside a QWidget with QPainter::drawPixmap() : QPixmap _source = "/.../.png"; painter.setRenderHint(QPainter::HighQualityAntialiasing); painter.drawPixmap(rect(), _source); but in comparing to QLabel (for example) and in lower size (19*19 in my case) the result isn't perfect. What can I do? ****Edit**** QLabel with pixmap @ size 19*19: My painting @ size 19*19 via SmoothPixmapTransform render type: 回答1: You are setting the wrong render hint, you need QPainter:

问题 I work at my homework in Qt Creator, where I paint to QWidget and I need to save some part of this QWdiget. I tried to solve this problem: QPixmap pixmap; pixmap.copy(rectangle); // rectangle is part of QWidget, which I need to save pixmap.save("example.png"); Thank you for help. 回答1: You can use QWidget::render for this. Assuming rectangle is a QRect: QPixmap pixmap(rectangle->size()); widget->render(&pixmap, QPoint(), QRegion(rectangle)); 回答2: From QWidget::Grab: QPixmap QWidget::grab(const

问题 I am trying to piece together PyQt5 based image viewer Python code from various sources and extend capability to crop regions of interest (ROI) within loaded images. The issue is that the mapped coordinates and mouse clicks consider scroll bar and menu bar when determining pixel locations. Following is the code that loads image and provide bounding box capability, but I cannot seem to draw/crop boxes accurately due to the offset. from PyQt5.QtCore import QDir, Qt from PyQt5.QtGui import

问题 Simple situation: I have an object, which has a QPixmap member. Object first created (pixmap is null now), then pixmap readed from data base and inserted in object. I need to insert that pixmap in html code () and display that html code in a QLabel but I have no idea how to make it, because pixmap's path is unknown. I know how to insert images from resource files and from files on my hard-disk, but it isn't that case. I was using QMimeSourceFactory class on qt 3.3.4, but on 4.6.2 it is

问题 I'm a newbie to Qt/Embedded. I want to use QPainter to draw stuff on a QPixmap , which will be added to QGraphicsScene . Here is my code. But it does not show the drawings on the pixmap. It shows only the black pixmap. int main(int argc, char **argv) { QApplication a(argc, argv); QMainWindow *win1 = new QMainWindow(); win1->resize(500,500); win1->show(); QGraphicsScene *scene = new QGraphicsScene(win1); QGraphicsView view(scene, win1); view.show(); view.resize(500,500); QPixmap *pix = new

问题 I'm a newbie to Qt/Embedded. I want to use QPainter to draw stuff on a QPixmap , which will be added to QGraphicsScene . Here is my code. But it does not show the drawings on the pixmap. It shows only the black pixmap. int main(int argc, char **argv) { QApplication a(argc, argv); QMainWindow *win1 = new QMainWindow(); win1->resize(500,500); win1->show(); QGraphicsScene *scene = new QGraphicsScene(win1); QGraphicsView view(scene, win1); view.show(); view.resize(500,500); QPixmap *pix = new

问题 I am working on a sensor-based Python application built on a PyQt4 GUI. The sensor is generating 16-bit measurements... 256 16-bit "pixels" per "line". A square "image" is acquired by obtaining 256 lines, resulting in a (256,256) Numpy array of 16-bit numbers. I simply want to display this as a grayscale image. The sensor loop is running in a QThread and emits a QImage signal. The signal connects to a slot that renders the data in the main GUI by packing it into a 32-bit RGB image. Of course,