A start-up script for keeping text in Space Center vertically centered.

auto_center_sc.py

# menuTitle: (Start-up) Auto-Vertically-Center in Space Center

from mojo.UI import CurrentSpaceCenter, CurrentSpaceCenterWindow
from mojo.subscriber import Subscriber, registerSpaceCenterSubscriber, registerSubscriberEvent, getRegisteredSubscriberEvents


class AutoCenterSC(Subscriber):
    '''
    Automatically vertically center the text in Space Center when things change.
    
    Ryan Bugden
    2024.12.19
    '''
    
    debug = False
    
    def build(self):
        self.csc = self.getSpaceCenter()
        
    def get_lineview_height(self):
        '''Returns the height of the window’s preview area.'''
        l, t, w, h = CurrentSpaceCenterWindow().w.getPosSize()
        _, _, _, top_h = self.csc.top.getPosSize()
        h = h - top_h
        return h
        
    def get_text_pos_info(self):
        '''
        Returns the bottom-most and top-most bounds, and total height 
        of the glyphs represented in Space Center.
        '''
        if not self.csc:
            return None, None, None
        f = self.csc.font
        lines_of_g_records = self.csc.glyphLineView.contentView()._glyphRecordsToDraw
        if lines_of_g_records:
            ps = self.csc.getPointSize()
            upm = self.csc.font.info.unitsPerEm
            offset = self.csc.getOffset()
            line_height = (self.csc.getLineHeight() + upm) * (ps / upm)

            bot = -line_height * (len(lines_of_g_records) - 1) - f.info.descender * (ps / upm)
            top = f.info.capHeight * (ps / upm) - f.info.descender * (ps / upm)
            bot_y = line_height - bot + offset[1]
            top_y = line_height - top + offset[1]
            
            height = f.info.capHeight * (ps / upm) + line_height * (len(lines_of_g_records) - 1)  # top - bot
            if self.debug:
                print()
                print("offset", offset)
                print("bot, top", round(bot_y, 1), round(top_y, 1))
                print("line-height", line_height)
                print("check—this should be zero", (top - bot) - height)
            return bot_y, top_y, height
        return None, None, None

    def update_y_offset(self):
        bot_y, top_y, height = self.get_text_pos_info()
        if not height:
            return
        lineview_height = self.get_lineview_height()
        height_diff = lineview_height - height

        if self.debug:
            print("lineview_height", lineview_height)
            print("glyphs_height", height)
            print("height_diff", height_diff)
        # Only adjust if text height is less than line-view height.
        if height_diff > 0:
            # Calculate padding for vertical centering
            top_pad = top_y
            bot_pad = lineview_height - bot_y
            des_pad = int((top_pad + bot_pad) / 2)  # Desired padding for both top and bottom
            pad_diff = des_pad - top_pad  # Difference to adjust
            off_x, off_y = self.csc.getOffset()  # Get current offset
            self.csc.setOffset((off_x, off_y + pad_diff))  # Update offset with difference
        
    spaceCenterDidChangeTextDelay = 0
    def spaceCenterDidChangeText(self, info):
        if self.debug: print("\nText changed in Space Center. Changing offset.")
        self.update_y_offset()
        
    spaceCenterDidKeyUpDelay = 0
    def spaceCenterDidKeyUp(self, info):
        if self.debug: print("\nKey hit in Space Center. Changing offset.")
        self.update_y_offset()
    
        
        
if __name__ == "__main__":
    registerSpaceCenterSubscriber(AutoCenterSC)