Behavior of “geometry” Property and “show” Method in PySide


I am developing applications that runs on Linux and Windows using PySide. In the process, I recently, so embarrassed a lot for the behavior of the “geometry” property of QMainWindow differs between Windows and Linux, so I investigated in detail.

Introduction

I wanted to do the following.

After the minimize, maximize, and full screen sized the main window, I want to know the current size of the window by code.

By running the QWidget.showMaximized / Minimized / FullScreen method, it is possible to change the window size to be displayed. (In the reference, there is a description indicating that showFullScreen() may not work well with X Window. But there is no inconvenience for now in use my range.) However, as described below, to know the display size from the current code, it works well on Windows, but it did not work on Linux.

How to Investigate

I have created the program that, by running each method show, showMaximized, showMinimized, showFullScreen, showNormal and setGeometry for QMainWindow, you can see how “geometry” property change. (Because it is unable to verify the value while displaying the window if you run the method before event loop, I made the methods run with delay of 100msec by QTimer. (Because the windows are displayed, the screen flickers a little at run time.)

Result

Here are the results of running checkShow.py, in the above-mentioned, on Windows7, Xubunutu13.04 and Ubunutu13.04 in the same PC (with VirtualBox environment: Host Windows, Guset Linux) with a screen size of 1920×1080. I listed the value of the “geometry” of the property at each stage. (It cut the redundant part of the actual display.)

The values of the QRect are, the first two are the position (the coordinates of the upper left) and the following two are the size (width x length).

On Windows

On Xubuntu/Ubuntu

The results on Ubuntu and Xubuntu were the same.

Summary

From the above results, I’ve found the following facts about “geometry” property.

  • Both on Windows and Linux, the value before running show() is (0, 0, 640, 480). (I think that it is VGA size).
  • After running show(), size is changed to 200×100 on both OS. However, the display position differs by OS. On Linux, it is the upper-left corner. And on Windows, it is shifted slightly to the lower right.
  • On Windows, after running showMaximized/FullScreen/Normal, “geometry” is set to the size of the window that is actually displayed. However, on Linux, those methods do not change the “geometry”.(Display itself is changed to be maximize or full sized or normalized. These facts mean that the value of the “geometry” and the actual window that is displayed does not match.)
  • showMinimized() method does not change “geometry” on Windows (also Linux). Perhaps, it seems that minimize is equivalent to be invisible.
  • Of course, setGeometry change the “geometry” on both OS.

From these results, you can find that on Windows you can know the current window size from “geometry” property, but there is a possibility that the current window size does not match the “geometry” in the case of Linux. On Linux, if you want to match the window size and the “geometry”, you should culculate the size of your own and run setGeometry().

[Related Site]
junf/checkshow

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To Display Images in Full-Screen by PySide


Introduction

Recently, I started Python programming to make applications on multi-platform. I selected “PySide” as a GUI library, and have been having trial and error in various ways. From those, I would like to post articles as a result of playing my particular interest. This time, I will describe how to display image in the full screen.

In addition, although 2.x mainstream is still Python, because movement to migrate to 3.x is likely to be activated in the future and 3.x is suitable to support Japanese language, I am programming in Python3.3. Therefore, please note the following code does not take into account any operation in 2.x.

Display an Image

First, I’ll try to make a code to display an image in PySide. You will see the JPEG file called “hoge.jpg”.

Read the image by the “QPixmap” object, set it to “QLabel” object by “setPixmap()” and display it by “show()” method. Although you would think that “label” is for displaying “text”, “QLabel” will function as a screen for image and text.

Window appears on the desktop as follows.
normal

Display Image in Full Screen

By changing “show()” to “showFullScreen()” in line 8, you can achieve the full-screen display.

It is displayed in full screen as follows. There is no frame of the window.
full

However, “close button” does not appear in full screen state. You will need to be able to release the full screen by handling the key event. (If you happen to display in full screen without any measures, switch to another task by ALT + TAB, and then you can close the application from the taskbar.)

Get the Key Events of QLabel

“QLabel”, as one of the parts of GUI, is inherit “QWidget”. It has the method “keyPressEvent” to handle the key events.

Define a class called “Screen” that inherits from “QLabel”, then you are going to be able to handle the ESC key to override the “keyPressEvent”.

If you press the ESC key, display is switched in maximum display / full screen. Please note that in order to return to the normal display, you’re calling the “showNormal()”.

By using this “Screen” class instead of QLabel, you will respond to the ESC key.

If you press the ESC key in the state of being full screen display, display change to maximum as shown below. If in this state, you will be able to terminate the program in close button.
max

The way of the adjustment of display position, please refer to the reference of “QLabel”.

In addition, since I have prepared here the complete code. Prepare a “hoge.jpg” and try it.

[Rlated Sites]
junf/PySideSamples · GitHub

[Rlated Articles]

  1. Display Images in Full-Screen by Qt, Multi-Platform GUI Lib | DeVlog – Fly With Your Devil’s Wings –
  2. Behavior of “geometry” Property and “show” Method in PySide | DeVlog – Fly With Your Devil’s Wings –
  3. Display Image While Sliding by PySide | DeVlog – Fly With Your Devil’s Wings –
  4. Fade in / Fade-out Images by PySide | DeVlog – Fly With Your Devil’s Wings –
  5. Realize Zoom-in and Zoom-out the Image in PySide | DeVlog – Fly With Your Devil’s Wings –

JDK and Android SDK Installation on Ubuntu


I’ve been developing Android application on Windows. But recently, I tried to create an environment in Linux (Ubuntu/Xubuntu). In this article, I will describe the installation of JDK and Android SDK that is required before installing IDE. (It is assumed that without the use of ADT Bundle, we install separately JDK/SDK and IDE.)

Installation of JDK

JDK is updated frequently. So I looked for package management. Then I found that Oracle Java (JDK) 6 / 7 / 8 Installer PPA : “WebUpd8” team provides PPA. This PPA downloads and run the Oracle installer.

Install as follows. Along the way, you are prompted to agree to Oracle license. Then agree.

In the last line, you are sure the installation was successful.
At the result, in my environment, the JDK is installed in /usr/lib/jvm/java-7-oracle.

Installation of Android SDK

Following Android SDK | Android Developers, I have installed the Android SDK.

  1. First, there is the following entry in SYSTEM REQUIREMENTS – Linux.

    64-bit distributions must be capable of running 32-bit applications.

    My Environment is 64bit-Xubuntu. So I installed ia32-libs. (It is not necessary for 32bit OS.)

  2. Next, from DOWNLOAD FOR OTHER PLATFORMS, download Linux 32 & 64-bit package. (Suppose /home/hoge/Downloads/android-sdk_r21.1-linux.tgz)
    * Currently, there is a package called ADT Bundle environment, including Eclipse. However, in this article, it is assumed that you install IDE separately.
  3. In the home directory, make appropriate directory (here, suppose “Development”), and extract files there.

  4. It is useful to make a path to “tools” directory. So add the following line in ~/.bashrc.

    In order to apply the path, do the following.

  5. Update the SDK. (Because SDK for all platform will be downloaded, it will take a lot of time.)

  6. Start the SDK Manager to check the results. (In my environment, the sources has not been downloaded. So I downloaded them.)

  7. For other commands for android, check with –help option.

After this, you can set up favorite IDE, such as IntelliJ or Eclipse, and start development.

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