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InteractiveViewer

Allows users to pan, zoom, and rotate the provided content.

Examples​

Live example

Basic Example​

import flet as ft


def main(page: ft.Page):
    page.add(
        ft.InteractiveViewer(
            min_scale=0.1,
            max_scale=15,
            boundary_margin=ft.margin.all(20),
            on_interaction_start=lambda e: print(e),
            on_interaction_end=lambda e: print(e),
            on_interaction_update=lambda e: print(e),
            content=ft.Image(
                src="https://picsum.photos/500/500",
            ),
        )
    )


ft.app(main)

Properties​

alignment​

Alignment of the content within.

Value is of type Alignment.

bgcolor​

The background color.

boundary_margin​

A margin for the visible boundaries of the content.

Value is of type Margin.

clip_behavior​

How to clip the content.

Value is of type ClipBehavior and defaults to ClipBehavior.HARD_EDGE.

constrained​

Whether the normal size constraints at this point in the widget tree are applied to the child.

content​

The Control to be transformed by the InteractiveViewer.

interaction_end_friction_coefficient​

Changes the deceleration behavior after a gesture. Must be greater than 0.

Value is of type float and defaults to 0.0000135.

interaction_update_interval​

The interval (in milliseconds) at which the on_interaction_update event is fired.

Value is of type int and defaults to 0.

max_scale​

The maximum allowed scale. Must be greater than or equal to min_scale.

Value is of type float and defaults to 2.5.

min_scale​

The minimum allowed scale. Must be greater than 0 and less than or equal to max_scale.

Value is of type float and defaults to 0.8.

pan_enabled​

Whether panning is enabled.

Value is of type bool and defaults to True.

scale_enabled​

Whether scaling is enabled.

Value is of type bool and defaults to True.

scale_factor​

The amount of scale to be performed per pointer scroll.

Value is of type float and defaults to 200.0.

trackpad_scroll_causes_scale​

Whether scrolling up/down on a trackpad should cause scaling instead of panning.

Value is of type bool and defaults to False.

Methods​

pan(dx, dy)​

Pans the InteractiveViewer by a specific amount.

It has the following parameters:

  • dx: The number of pixels to pan on the x-axis.
  • dy: The number of pixels to pan on the y-axis.

reset()​

Resets the InteractiveViewer to its initial state. By default, the reset happens with no animation (immediately).

It has the following parameters:

  • animation_duration: Animates the reset with the given duration. Value is of type DurationValue.

restore_state()​

Restores the state of the InteractiveViewer previously saved using save_state.

save_state()​

Saves the current state of the InteractiveViewer, which can be restored later using restore_state.

zoom(factor);​

Zooms in or out to a specific level.

It has the following parameters:

  • factor: The zoom factor. Values below 1 will zoom out, values above 1 will zoom in.

Events​

on_interaction_end​

Fires when the user ends a pan or scale gesture.

Event handler argument is of type InteractiveViewerInteractionEndEvent.

on_interaction_start​

Fires when the user begins a pan or scale gesture.

Event handler argument is of type InteractiveViewerInteractionStartEvent.

on_interaction_update​

Fires when the user updates a pan or scale gesture.

Event handler argument is of type InteractiveViewerInteractionUpdateEvent.