Implement this interface to handle events when window rendering is disabled (off-screen rendering). The methods of this class will be called on the UI thread. In order to create windowless browsers the windowless_rendering_enabled setting must be set to true.
Table of contents:
Off-screen rendering examples:
- Kivy
- Panda3D - tested with v31
- pygame + PyOpenGL - tested with v31, more info on this example on the Forum in this post
- cefpython_offscreen_no_UI_framework.py - most basic usage of OSR to take a screenshot of a page
Callbacks available in upstream CEF, but not yet exposed in CEF Python (see src/include/cef_render_handler.h):
- GetScreenInfo
- OnImeCompositionRangeChanged
| Parameter | Type |
|---|---|
| browser | Browser |
| rect_out | list[x,y,width,height] |
| Return | bool |
Called to retrieve the root window rectangle in screen coordinates. Return true if the rectangle was provided.
| Parameter | Type |
|---|---|
| browser | Browser |
| rect_out | list[x,y,width,height] |
| Return | bool |
Called to retrieve the view rectangle which is relative to screen coordinates. Return true if the rectangle was provided.
| Parameter | Type |
|---|---|
| browser | Browser |
| rect_out | list[x,y,width,height] |
| Return | bool |
Called to retrieve the simulated screen rectangle. Return true if the rectangle was provided.
| Parameter | Type |
|---|---|
| browser | Browser |
| view_x | int |
| view_y | int |
| screen_coordinates_out | list[x,y] |
| Return | bool |
Called to retrieve the translation from view coordinates to actual screen coordinates. Return true if the screen coordinates were provided.
| Parameter | Type |
|---|---|
| browser | Browser |
| show | bool |
| Return | void |
Called when the browser wants to show or hide the popup widget. The popup should be shown if |show| is true and hidden if|show| is false.
| Parameter | Type |
|---|---|
| browser | Browser |
| rect_out | list[x,y,width,height] |
| Return | void |
Called when the browser wants to move or resize the popup widget. |rect_out| contains the new location and size.
| Parameter | Type |
|---|---|
| browser | Browser |
| element_type | PaintElementType |
| dirty_rects | list[[x,y,width,height],[..]] |
| paint_buffer | PaintBuffer |
| width | int |
| height | int |
| Return | void |
Called when an element should be painted. Pixel values passed to this method are scaled relative to view coordinates based on the value of CefScreenInfo.device_scale_factor returned from GetScreenInfo. |type| indicates whether the element is the view or the popup widget. |buffer| contains the pixel data for the whole image. |dirty_rects| contains the set of rectangles in pixel coordinates that need to be repainted. |buffer| will be |width|*|height|*4 bytes in size and represents a BGRA image with an upper-left origin.
Important: Do not keep reference to |paint_buffer| after this method returns.
PaintElementType enum:
- cef.PET_VIEW
- cef.PET_POPUP
| Parameter | Type |
|---|---|
| browser | Browser |
| cursor | CursorHandle |
| Return | void |
Called when the browser's cursor has changed. If |type| is CT_CUSTOM then |custom_cursor_info| will be populated with the custom cursor information.
CursorHandle is an int pointer.
| Parameter | Type |
|---|---|
| browser | Browser |
| Return | void |
Called when the scroll offset has changed.
| Parameter | Type |
|---|---|
| browser | Browser |
| drag_data | DragData |
| allowed_ops | int |
| x | int |
| y | int |
| Return | void |
Description from upstream CEF:
Called when the user starts dragging content in the web view. Contextual information about the dragged content is supplied by |drag_data|. (|x|, |y|) is the drag start location in screen coordinates. OS APIs that run a system message loop may be used within the StartDragging call.
Return false to abort the drag operation. Don't call any of CefBrowserHost::DragSourceEnded methods after returning false.
Return true to handle the drag operation. Call CefBrowserHost::DragSourceEndedAt and DragSourceSystemDragEnded either synchronously or asynchronously to inform the web view that the drag operation has ended.
| Parameter | Type |
|---|---|
| browser | Browser |
| operation | int |
| Return | void |
Description from upstream CEF:
Called when the web view wants to update the mouse cursor during a drag & drop operation. |operation| describes the allowed operation (none, move, copy, link).
See Browser.DragSourceEndedAt for a list of values for the operation enum.