'''
Image
=====
The :class:`Image` widget is used to display an image::
Example in python::
wimg = Image(source='mylogo.png')
Kv Example::
Image:
source: 'mylogo.png'
size: self.texture_size
Asynchronous Loading
--------------------
To load an image asynchronously (for example from an external webserver), use
the :class:`AsyncImage` subclass::
aimg = AsyncImage(source='http://mywebsite.com/logo.png')
This can be useful as it prevents your application from waiting until the image
is loaded. If you want to display large images or retrieve them from URL's,
using :class:`AsyncImage` will allow these resources to be retrieved on a
background thread without blocking your application.
Alignment
---------
By default, the image is centered and fits inside the widget bounding box.
If you don't want that, you can set `allow_stretch` to True and `keep_ratio`
to False.
You can also inherit from Image and create your own style. For example, if you
want your image to be greater than the size of your widget, you could do::
class FullImage(Image):
pass
And in your kivy language file::
<-FullImage>:
canvas:
Color:
rgb: (1, 1, 1)
Rectangle:
texture: self.texture
size: self.width + 20, self.height + 20
pos: self.x - 10, self.y - 10
'''
__all__ = ('Image', 'AsyncImage')
from kivy.uix.widget import Widget
from kivy.core.image import Image as CoreImage
from kivy.resources import resource_find
from kivy.properties import StringProperty, ObjectProperty, ListProperty, \
AliasProperty, BooleanProperty, NumericProperty, ColorProperty
from kivy.logger import Logger
# delayed imports
Loader = None
[docs]class Image(Widget):
'''Image class, see module documentation for more information.
'''
source = StringProperty(None)
'''Filename / source of your image.
:attr:`source` is a :class:`~kivy.properties.StringProperty` and
defaults to None.
'''
texture = ObjectProperty(None, allownone=True)
'''Texture object of the image. The texture represents the original, loaded
image texture. It is stretched and positioned during rendering according to
the :attr:`allow_stretch` and :attr:`keep_ratio` properties.
Depending of the texture creation, the value will be a
:class:`~kivy.graphics.texture.Texture` or a
:class:`~kivy.graphics.texture.TextureRegion` object.
:attr:`texture` is an :class:`~kivy.properties.ObjectProperty` and defaults
to None.
'''
texture_size = ListProperty([0, 0])
'''Texture size of the image. This represents the original, loaded image
texture size.
.. warning::
The texture size is set after the texture property. So if you listen to
the change on :attr:`texture`, the property texture_size will not be
up-to-date. Use self.texture.size instead.
'''
def get_image_ratio(self):
if self.texture:
return self.texture.width / float(self.texture.height)
return 1.
mipmap = BooleanProperty(False)
'''Indicate if you want OpenGL mipmapping to be applied to the texture.
Read :ref:`mipmap` for more information.
.. versionadded:: 1.0.7
:attr:`mipmap` is a :class:`~kivy.properties.BooleanProperty` and defaults
to False.
'''
image_ratio = AliasProperty(get_image_ratio, bind=('texture',), cache=True)
'''Ratio of the image (width / float(height).
:attr:`image_ratio` is an :class:`~kivy.properties.AliasProperty` and is
read-only.
'''
color = ColorProperty([1, 1, 1, 1])
'''Image color, in the format (r, g, b, a). This attribute can be used to
'tint' an image. Be careful: if the source image is not gray/white, the
color will not really work as expected.
.. versionadded:: 1.0.6
:attr:`color` is a :class:`~kivy.properties.ColorProperty` and defaults to
[1, 1, 1, 1].
.. versionchanged:: 2.0.0
Changed from :class:`~kivy.properties.ListProperty` to
:class:`~kivy.properties.ColorProperty`.
'''
allow_stretch = BooleanProperty(False)
'''If True, the normalized image size will be maximized to fit in the image
box. Otherwise, if the box is too tall, the image will not be
stretched more than 1:1 pixels.
.. versionadded:: 1.0.7
:attr:`allow_stretch` is a :class:`~kivy.properties.BooleanProperty` and
defaults to False.
'''
keep_ratio = BooleanProperty(True)
'''If False along with allow_stretch being True, the normalized image
size will be maximized to fit in the image box and ignores the aspect
ratio of the image.
Otherwise, if the box is too tall, the image will not be stretched more
than 1:1 pixels.
.. versionadded:: 1.0.8
:attr:`keep_ratio` is a :class:`~kivy.properties.BooleanProperty` and
defaults to True.
'''
keep_data = BooleanProperty(False)
'''If True, the underlying _coreimage will store the raw image data.
This is useful when performing pixel based collision detection.
.. versionadded:: 1.3.0
:attr:`keep_data` is a :class:`~kivy.properties.BooleanProperty` and
defaults to False.
'''
anim_delay = NumericProperty(.25)
'''Delay the animation if the image is sequenced (like an animated gif).
If anim_delay is set to -1, the animation will be stopped.
.. versionadded:: 1.0.8
:attr:`anim_delay` is a :class:`~kivy.properties.NumericProperty` and
defaults to 0.25 (4 FPS).
'''
anim_loop = NumericProperty(0)
'''Number of loops to play then stop animating. 0 means keep animating.
.. versionadded:: 1.9.0
:attr:`anim_loop` is a :class:`~kivy.properties.NumericProperty` and
defaults to 0.
'''
nocache = BooleanProperty(False)
'''If this property is set True, the image will not be added to the
internal cache. The cache will simply ignore any calls trying to
append the core image.
.. versionadded:: 1.6.0
:attr:`nocache` is a :class:`~kivy.properties.BooleanProperty` and defaults
to False.
'''
def get_norm_image_size(self):
if not self.texture:
return list(self.size)
ratio = self.image_ratio
w, h = self.size
tw, th = self.texture.size
# ensure that the width is always maximized to the container width
if self.allow_stretch:
if not self.keep_ratio:
return [w, h]
iw = w
else:
iw = min(w, tw)
# calculate the appropriate height
ih = iw / ratio
# if the height is too higher, take the height of the container
# and calculate appropriate width. no need to test further. :)
if ih > h:
if self.allow_stretch:
ih = h
else:
ih = min(h, th)
iw = ih * ratio
return [iw, ih]
norm_image_size = AliasProperty(get_norm_image_size,
bind=('texture', 'size', 'allow_stretch',
'image_ratio', 'keep_ratio'),
cache=True)
'''Normalized image size within the widget box.
This size will always fit the widget size and will preserve the image
ratio.
:attr:`norm_image_size` is an :class:`~kivy.properties.AliasProperty` and
is read-only.
'''
def __init__(self, **kwargs):
self._coreimage = None
self._loops = 0
update = self.texture_update
fbind = self.fbind
fbind('source', update)
fbind('mipmap', update)
super().__init__(**kwargs)
def texture_update(self, *largs):
self.set_texture_from_resource(self.source)
def set_texture_from_resource(self, resource):
if not resource:
self._clear_core_image()
return
source = resource_find(resource)
if not source:
Logger.error('Image: Not found <%s>' % resource)
self._clear_core_image()
return
if self._coreimage:
self._coreimage.unbind(on_texture=self._on_tex_change)
try:
self._coreimage = image = CoreImage(
source,
mipmap=self.mipmap,
anim_delay=self.anim_delay,
keep_data=self.keep_data,
nocache=self.nocache
)
except Exception:
Logger.error('Image: Error loading <%s>' % resource)
self._clear_core_image()
image = self._coreimage
if image:
image.bind(on_texture=self._on_tex_change)
self.texture = image.texture
def on_anim_delay(self, instance, value):
if self._coreimage is None:
return
self._coreimage.anim_delay = value
if value < 0:
self._coreimage.anim_reset(False)
def on_texture(self, instance, value):
self.texture_size = value.size if value else [0, 0]
def _clear_core_image(self):
if self._coreimage:
self._coreimage.unbind(on_texture=self._on_tex_change)
self.texture = None
self._coreimage = None
self._loops = 0
def _on_tex_change(self, *largs):
# update texture from core image
self.texture = self._coreimage.texture
ci = self._coreimage
if self.anim_loop and ci._anim_index == len(ci._image.textures) - 1:
self._loops += 1
if self.anim_loop == self._loops:
ci.anim_reset(False)
self._loops = 0
[docs] def reload(self):
'''Reload image from disk. This facilitates re-loading of
images from disk in case the image content changes.
.. versionadded:: 1.3.0
Usage::
im = Image(source = '1.jpg')
# -- do something --
im.reload()
# image will be re-loaded from disk
'''
self.remove_from_cache()
old_source = self.source
self.source = ''
self.source = old_source
[docs] def remove_from_cache(self):
'''Remove image from cache.
.. versionadded:: 2.0.0
'''
if self._coreimage:
self._coreimage.remove_from_cache()
def on_nocache(self, *args):
if self.nocache:
self.remove_from_cache()
if self._coreimage:
self._coreimage._nocache = True
[docs]class AsyncImage(Image):
'''Asynchronous Image class. See the module documentation for more
information.
.. note::
The AsyncImage is a specialized form of the Image class. You may
want to refer to the :mod:`~kivy.loader` documentation and in
particular, the :class:`~kivy.loader.ProxyImage` for more detail
on how to handle events around asynchronous image loading.
.. note::
AsyncImage currently does not support properties
:attr:`anim_loop` and :attr:`mipmap` and setting those properties will
have no effect.
'''
__events__ = ('on_error', 'on_load')
def __init__(self, **kwargs):
self._found_source = None
self._coreimage = None
global Loader
if not Loader:
from kivy.loader import Loader
self.fbind('source', self._load_source)
super().__init__(**kwargs)
def _load_source(self, *args):
source = self.source
if not source:
self._clear_core_image()
return
if not self.is_uri(source):
source = resource_find(source)
if not source:
Logger.error('AsyncImage: Not found <%s>' % self.source)
self._clear_core_image()
return
self._found_source = source
self._coreimage = image = Loader.image(
source,
nocache=self.nocache,
mipmap=self.mipmap,
anim_delay=self.anim_delay
)
image.bind(
on_load=self._on_source_load,
on_error=self._on_source_error,
on_texture=self._on_tex_change
)
self.texture = image.texture
def _on_source_load(self, value):
image = self._coreimage.image
if not image:
return
self.texture = image.texture
self.dispatch('on_load')
def _on_source_error(self, instance, error=None):
self.dispatch('on_error', error)
def on_error(self, error):
pass
def on_load(self, *args):
pass
def is_uri(self, filename):
proto = filename.split('://', 1)[0]
return proto in ('http', 'https', 'ftp', 'smb')
def _clear_core_image(self):
if self._coreimage:
self._coreimage.unbind(on_load=self._on_source_load)
super()._clear_core_image()
self._found_source = None
def _on_tex_change(self, *largs):
if self._coreimage:
self.texture = self._coreimage.texture
def texture_update(self, *largs):
pass
[docs] def remove_from_cache(self):
if self._found_source:
Loader.remove_from_cache(self._found_source)
super().remove_from_cache()
