Multi-touch zoom

static/picture-annotation.py

@@ -813,38 +813,40 @@ def on_touch_move(event):

                                
                                
                                
                            
                                
                                    
                                        
                                            813  
                                                if event.touches.length == 2:
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            814  
                                                    event.preventDefault()
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            815  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        816 +
                                                # Finger positions.
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            817  
                                                    current_positions = [
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            818  
                                                        (event.touches[0].clientX, event.touches[0].clientY),
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            819  
                                                        (event.touches[1].clientX, event.touches[1].clientY)
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            820  
                                                    ]
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            821  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            822  
                                                    current_distance = calculate_distance(event.touches)
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        822 -
                                                zoom_factor = current_distance / last_touch_distance
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        823 -
                                                new_scale = max(0.0625, min(64, scale * zoom_factor))
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        824 -
                                                scale_factor = new_scale / scale
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        823 +
                                                # Ignore small movements.
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        824 +
                                                if abs(current_distance - last_touch_distance) > 16:
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        825 +
                                                    zoom_factor = current_distance / last_touch_distance
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        826 +
                                                    new_scale = max(0.0625, min(64, scale * zoom_factor))
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            827  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        828 +
                                                # Finger midpoint.
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            829  
                                                    midpoint_x = (current_positions[0][0] + current_positions[1][0]) / 2
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            830  
                                                    midpoint_y = (current_positions[0][1] + current_positions[1][1]) / 2
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            831  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        829 -
                                                rect = zone.getBoundingClientRect()
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        830 -
                                                content_mid_x = (midpoint_x - rect.left - translate_x) / scale
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        831 -
                                                content_mid_y = (midpoint_y - rect.top - translate_y) / scale
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        832 -
                                        
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        833 -
                                                translate_x = midpoint_x - content_mid_x * new_scale
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        834 -
                                                translate_y = midpoint_y - content_mid_y * new_scale
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        832 +
                                                # Compute translation for zooming around the midpoint.
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        833 +
                                                tx, ty = compute_zoom_translation_around_point(zone, midpoint_x, midpoint_y, scale, new_scale)
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            834  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        835 +
                                                # Compute translation for panning.
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            836  
                                                    delta_x = sum(p[0] - lp[0] for p, lp in zip(current_positions, last_touch_positions)) / 2
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            837  
                                                    delta_y = sum(p[1] - lp[1] for p, lp in zip(current_positions, last_touch_positions)) / 2
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            838  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        839 -
                                                translate_x += delta_x
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        840 -
                                                translate_y += delta_y
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        839 +
                                                translate_x += delta_x - tx
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        840 +
                                                translate_y += delta_y - ty
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            841  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        842 +
                                                # Update state.
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            843  
                                                    scale = new_scale
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            844  
                                                    last_touch_positions = current_positions
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            845  
                                                    last_touch_distance = current_distance
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            846  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            847  
                                                    update_transform()
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            848  
                                            
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        849 +
                                        
                                        
                                        
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            850  
                                            def on_touch_end(event):
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            851  
                                                global last_touch_positions, last_touch_distance
                                        
                                        
                                            
                                            
                                            
                                            
                                        
                                    
                                
                                
                                
                            
                                
                                    
                                        
                                            852  
                                                if event.touches.length < 2: