Ajout du GUI

kivy/core/text/text_pango.py

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+'''
+Pango text provider
+===================
+
+.. versionadded:: 1.11.0
+
+.. warning::
+    The low-level Pango API is experimental, and subject to change without
+    notice for as long as this warning is present.
+
+
+Installation
+------------
+
+1. Install pangoft2 (`apt install libfreetype6-dev libpango1.0-dev
+   libpangoft2-1.0-0`) or ensure it is available in pkg-config
+2. Recompile kivy. Check that pangoft2 is found `use_pangoft2 = 1`
+3. Test it! Enforce the text core renderer to pango using environment variable:
+   `export KIVY_TEXT=pango`
+
+This has been tested on OSX and Linux, Python 3.6.
+
+
+Font context types for FontConfig+FreeType2 backend
+---------------------------------------------------
+
+* `system://` - `FcInitLoadConfigAndFonts()`
+* `systemconfig://` - `FcInitLoadConfig()`
+* `directory://<PATH>` - `FcInitLoadConfig()` + `FcAppFontAddDir()`
+* `fontconfig://<PATH>` - `FcConfigCreate()` + `FcConfigParseAndLoad()`
+* Any other context name - `FcConfigCreate()`
+
+
+Low-level Pango access
+----------------------
+
+Since Kivy currently does its own text layout, the Label and TextInput widgets
+do not take full advantage of Pango. For example, line breaks do not take
+language/script into account, and switching alignment per paragraph (for bi-
+directional text) is not supported. For advanced i18n requirements, we provide
+a simple wrapper around PangoLayout that you can use to render text.
+
+* https://developer.gnome.org/pango/1.40/pango-Layout-Objects.html
+* https://developer.gnome.org/pango/1.40/PangoMarkupFormat.html
+* See the `kivy/core/text/_text_pango.pyx` file @ `cdef class KivyPangoLayout`
+  for more information. Not all features of PangoLayout are implemented.
+
+.. python::
+    from kivy.core.window import Window  # OpenGL must be initialized
+    from kivy.core.text._text_pango import KivyPangoLayout
+    layout = KivyPangoLayout('system://')
+    layout.set_markup('<span font="20">Hello <b>World!</b></span>')
+    tex = layout.render_as_Texture()
+
+
+Known limitations
+-----------------
+
+* Pango versions older than v1.38 has not been tested. It may work on
+  some systems with older pango and newer FontConfig/FreeType2 versions.
+* Kivy's text layout is used, not Pango. This means we do not use Pango's
+  line-breaking feature (which is superior to Kivy's), and we can't use
+  Pango's bidirectional cursor helpers in TextInput.
+* Font family collissions can happen. For example, if you use a `system://`
+  context and add a custom `Arial.ttf`, using `arial` as the `font_family`
+  may or may not draw with your custom font (depending on whether or not
+  there is already a system-wide "arial" font installed)
+* Rendering is inefficient; the normal way to integrate Pango would be
+  using a dedicated PangoLayout per widget. This is not currently practical
+  due to missing abstractions in Kivy core (in the current implementation,
+  we have a dedicated PangoLayout *per font context,* which is rendered
+  once for each LayoutWord)
+'''
+
+__all__ = ('LabelPango', )
+
+from types import MethodType
+from os.path import isfile
+from kivy.resources import resource_find
+from kivy.core.text import LabelBase, FontContextManagerBase
+from kivy.core.text._text_pango import (
+        KivyPangoRenderer,
+        kpango_get_extents,
+        kpango_get_ascent,
+        kpango_get_descent,
+        kpango_find_base_dir,
+        kpango_font_context_exists,
+        kpango_font_context_create,
+        kpango_font_context_destroy,
+        kpango_font_context_add_font,
+        kpango_font_context_list,
+        kpango_font_context_list_custom,
+        kpango_font_context_list_families)
+
+
+class LabelPango(LabelBase):
+
+    _font_family_support = True
+
+    def __init__(self, *largs, **kwargs):
+        self.get_extents = MethodType(kpango_get_extents, self)
+        self.get_ascent = MethodType(kpango_get_ascent, self)
+        self.get_descent = MethodType(kpango_get_descent, self)
+        super(LabelPango, self).__init__(*largs, **kwargs)
+
+    find_base_direction = staticmethod(kpango_find_base_dir)
+
+    def _render_begin(self):
+        self._rdr = KivyPangoRenderer(*self._size)
+
+    def _render_text(self, text, x, y):
+        self._rdr.render(self, text, x, y)
+
+    def _render_end(self):
+        imgdata = self._rdr.get_ImageData()
+        del self._rdr
+        return imgdata
+
+
+class PangoFontContextManager(FontContextManagerBase):
+    create = staticmethod(kpango_font_context_create)
+    exists = staticmethod(kpango_font_context_exists)
+    destroy = staticmethod(kpango_font_context_destroy)
+    list = staticmethod(kpango_font_context_list)
+    list_families = staticmethod(kpango_font_context_list_families)
+    list_custom = staticmethod(kpango_font_context_list_custom)
+
+    @staticmethod
+    def add_font(font_context, filename, autocreate=True, family=None):
+        if not autocreate and not PangoFontContextManager.exists(font_context):
+            raise Exception("FontContextManager: Attempt to add font file "
+                            "'{}' to non-existing context '{}' without "
+                            "autocreate.".format(filename, font_context))
+        if not filename:
+            raise Exception("FontContextManager: Cannot add empty font file")
+        if not isfile(filename):
+            filename = resource_find(filename)
+        if not isfile(filename):
+            if not filename.endswith('.ttf'):
+                filename = resource_find('{}.ttf'.format(filename))
+        if filename and isfile(filename):
+            return kpango_font_context_add_font(font_context, filename)
+        raise Exception("FontContextManager: Attempt to add non-existent "
+                        "font file: '{}' to context '{}'"
+                        .format(filename, font_context))