[Sugar-devel] [PATCH sugar] Fix screenshot extension, port to cairo - SL #3906

[Simon Schampijer]

Thanks Manuel.

On 09/18/2012 06:38 AM, Manuel Quiñones wrote:
> 1. API fix, Gdk.Window now has get_width() and get_height(), not
>     get_size().

Yes.

> 2. Use cairo to make the screenshot: paint the window surface in a new
>     surface and then save it as png to the path that will be provided
>     to the datastore.
>
> 3. Use the same cairo code as in the toolkit-gtk3 to make a preview of
>     the screenshot surface, store it as an array of bytes.

Yes, as you say, same as in the toolkit. Is the right thing to do.

And it even works!

Please push,
    Simon

> Signed-off-by: Manuel Quiñones <manuq at laptop.org>
> ---
>   extensions/globalkey/screenshot.py | 53 ++++++++++++++++++++++++++------------
>   1 file changed, 36 insertions(+), 17 deletions(-)
>
> diff --git a/extensions/globalkey/screenshot.py b/extensions/globalkey/screenshot.py
> index d5b88ea..5abf15b 100644
> --- a/extensions/globalkey/screenshot.py
> +++ b/extensions/globalkey/screenshot.py
> @@ -18,6 +18,8 @@
>   import os
>   import tempfile
>   from gettext import gettext as _
> +import StringIO
> +import cairo
>
>   from gi.repository import Gtk
>   from gi.repository import Gdk
> @@ -38,15 +40,15 @@ def handle_key_press(key):
>       os.close(fd)
>
>       window = Gdk.get_default_root_window()
> -    width, height = window.get_size()
> -    x_orig, y_orig = window.get_origin()
> +    width, height = window.get_width(), window.get_height()
>
> -    screenshot = GdkPixbuf.Pixbuf(GdkPixbuf.Colorspace.RGB, has_alpha=False,
> -                                    bits_per_sample=8, width=width,
> -                                    height=height)
> -    screenshot.get_from_drawable(window, window.get_colormap(), x_orig,
> -                                    y_orig, 0, 0, width, height)
> -    screenshot.save(file_path, 'png')
> +    window_cr = Gdk.cairo_create(window)
> +    window_surface = window_cr.get_target()
> +    screenshot_surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
> +    cr = cairo.Context(screenshot_surface)
> +    cr.set_source_surface(window_surface)
> +    cr.paint()
> +    screenshot_surface.write_to_png(file_path)
>
>       client = GConf.Client.get_default()
>       color = client.get_string('/desktop/sugar/user/color')
> @@ -79,7 +81,7 @@ def handle_key_press(key):
>           jobject.metadata['title'] = title
>           jobject.metadata['keep'] = '0'
>           jobject.metadata['buddies'] = ''
> -        jobject.metadata['preview'] = _get_preview_data(screenshot)
> +        jobject.metadata['preview'] = _get_preview_data(screenshot_surface)
>           jobject.metadata['icon-color'] = color
>           jobject.metadata['mime_type'] = 'image/png'
>           jobject.file_path = file_path
> @@ -89,14 +91,31 @@ def handle_key_press(key):
>           del jobject
>
>
> -def _get_preview_data(screenshot):
> -    preview = screenshot.scale_simple(style.zoom(300), style.zoom(225),
> -                                      GdkPixbuf.InterpType.BILINEAR)
> -    preview_data = []
> +def _get_preview_data(screenshot_surface):
> +    screenshot_width = screenshot_surface.get_width()
> +    screenshot_height = screenshot_surface.get_height()
>
> -    def save_func(buf, data):
> -        data.append(buf)
> +    preview_width, preview_height = style.zoom(300), style.zoom(225)
> +    preview_surface = cairo.ImageSurface(cairo.FORMAT_ARGB32,
> +                                         preview_width, preview_height)
> +    cr = cairo.Context(preview_surface)
>
> -    preview.save_to_callback(save_func, 'png', user_data=preview_data)
> +    scale_w = preview_width * 1.0 / screenshot_width
> +    scale_h = preview_height * 1.0 / screenshot_height
> +    scale = min(scale_w, scale_h)
>
> -    return dbus.ByteArray(''.join(preview_data))
> +    translate_x = int((preview_width - (screenshot_width * scale)) / 2)
> +    translate_y = int((preview_height - (screenshot_height * scale)) / 2)
> +
> +    cr.translate(translate_x, translate_y)
> +    cr.scale(scale, scale)
> +
> +    cr.set_source_rgba(1, 1, 1, 0)
> +    cr.set_operator(cairo.OPERATOR_SOURCE)
> +    cr.paint()
> +    cr.set_source_surface(screenshot_surface)
> +    cr.paint()
> +
> +    preview_str = StringIO.StringIO()
> +    preview_surface.write_to_png(preview_str)
> +    return dbus.ByteArray(preview_str.getvalue())
>