[FIXED] Qt Designer - Using High Resolution. Need Low Resolution version

Issue

I designed a rather large GUI using QT designer on a high resolution screen. I am needing a version to deploy on low resolution screens. In the post: PyQt GUI size on high resolution screens I found a solution for converting from low resolution to high resolution by doing this:

# Handle high resolution displays:
    if hasattr(QtCore.Qt, 'AA_EnableHighDpiScaling'):
        QtWidgets.QApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling, True)
    if hasattr(QtCore.Qt, 'AA_UseHighDpiPixmaps'):
        QtWidgets.QApplication.setAttribute(QtCore.Qt.AA_UseHighDpiPixmaps, True)

However, in my case, I need the exact opposite. I need a way to handle a GUI that was designed for a high resolution screen to scale down to low resolution.

Solution

I ended up writing a small program to change the ratio within the ui file that was generated by Qt Designer. There are only four tags that I changed , , , and . This got it pretty close so that now I am able to tweak it with designer. I hope this helps someone else.

old_file = "old.ui"
new_file = "new.ui"
#Old resolution
oldx = 3840.0 
oldy = 2160.0
#New resolution
newx = 1360.0
newy = 768.0

ratiox = newx / oldx
ratioy = newy / oldy


def find_between( s, first, last ):
    start = s.index( first ) + len( first )
    end = s.index( last, start )
    return s[start:end]    

with open(old_file, 'r') as f:
    for line in f:
        if "<width>" in line:
            num = float(find_between(line, "<width>", "</width>"))
            #Fix resolution
            old_size = str(int(num))
            new_size = str(int(num * ratiox))
            w = line.replace(old_size, new_size)
        elif "<height>" in line:
            num = float(find_between(line, "<height>", "</height>"))
            #Fix resolution
            old_size = str(int(num))
            new_size = str(int(num * ratioy))
            w = line.replace(old_size, new_size)
        elif "<x>" in line:
            num = float(find_between(line, "<x>", "</x>"))
            #Fix resolution
            old_size = str(int(num))
            new_size = str(int(num * ratiox))
            w = line.replace(old_size, new_size)
        elif "<y>" in line:
            num = float(find_between(line, "<y>", "</y>"))
            #Fix resolution
            old_size = str(int(num))
            new_size = str(int(num * ratioy))
            w = line.replace(old_size, new_size)
        else:
            w = line
        with open('new_file.ui', 'a') as g:
            g.write(w)

Answered By - Mike C.