PyQT-Image-Viewer

Image viewer built with python and the Qt5 framework

Features

• Open jpg images using Ctrl + O or File menu -> Open
• Move around image using trackpad or mouse with scroll bars
• Zoom:
  • Zoom in using Ctrl + + or View Menu -> Zoom In
  • Zoom out using Ctrl + - or View Menu -> Zoom Out
  • Reset Zoom using Ctrl + R or View Menu -> Reset Zoom
• Edit Image Contrast:
  • Once image is loaded in, use Ctrl + F or View Menu -> Edit Image Contrast (Opens new small window with slider)
  • Move slider around to view changes
• Save Image:
  • Once image is edited, use Ctrl + S or File Menu -> Save Image to save image
  • Image will be saved in the directory of where the project is being run

Technical Implementation

• Utilized Python PyQt5 framework to run a native desktop application
• Opens file as a QImage and converts it to a QPixMap to render as a QLabel on application the user interacts with
• Zoom features are implemented using the scale and resize properties of QLabel
  • Scales image with a factor of +/- 25%
  • Reset zoom option just sets the resize back to original image size
• Contrast feature is implemented using the PIL/Pillow library to modify contrast levels
  • When image is opened, a image buffer is created before the QImage is converted to QPixMap
  • This buffer is loaded into PIL for modification
  • Meanwhile, a second window ContrastView is rendered on the screen with a simple slider (QSlider) that sets contrast levels
  • There is a onValueChanged property for the QSlider that is used to update the count value next to the slider and also used to pass the value into the ImageEnhancer from PIL for contrast level modifications
  • Once PIL modifies the image, the image needs to be converted back from PIL into a QImage to reset the QPixMap that is used to display the image to the user. This is done by leveraging ImageQt provided from PIL by casting the edited image into ImageQt which can then be passed onto the image label for setting the QPixMap
  • The image buffer is reset everytime a new image is opened
• Saving feature is implemented using the built-in save() function in the PIL library

How to run

• Install required dependencies using pip

pip install -r requirements.txt

• Or manually install dependencies

  • pip install PyQt5
  • pip install Pillow

• Run ImageViewer.py

python ImageViewer.py