Bug fixes for Attributes + Setters for Rectangle + Acceptance tests (#42)

Author: leifgehrmann

.gitignore

@@ -8,6 +8,9 @@ __pycache__
 # Build artifacts specific to pangocffi
 _generated
 
+# Test outputs
+/tests/acceptance/output
+
 # Virtualenv
 venv
 

pangocffi/attribute.py

@@ -15,13 +15,11 @@ class Attribute:
 
     def __init__(self):
         self._pointer = None
-        self._start_index = None
-        self._end_index = None
 
     @classmethod
     def _init_pointer(cls, pointer: ffi.CData) -> "Attribute":
         self = object.__new__(cls)
-        self._pointer = ffi.gc(pointer, pango.pango_attribute_destroy)
+        self._pointer = pointer
         return self
 
     @classmethod
@@ -59,7 +57,7 @@ def __eq__(self, other: "Attribute") -> bool:
 
     @property
     def start_index(self):
-        return self._start_index
+        return self._pointer.start_index
 
     @start_index.setter
     def start_index(self, start_index: int):
@@ -76,13 +74,12 @@ def start_index(self, start_index: int):
             "start_index is too low"
         assert start_index < pango.PANGO_ATTR_INDEX_TO_TEXT_END, \
             "start_index is too high"
-        self._start_index = start_index
         start = ffi.cast("guint", start_index)
         self._pointer.start_index = start
 
     @property
     def end_index(self):
-        return self._end_index
+        return self._pointer.end_index
 
     @end_index.setter
     def end_index(self, end_index: int):
@@ -98,9 +95,8 @@ def end_index(self, end_index: int):
         assert isinstance(end_index, int), "end_index isn't a int"
         assert end_index <= pango.PANGO_ATTR_INDEX_TO_TEXT_END, \
             "end_index is too high"
-        self._end_index = end_index
         end = ffi.cast("guint", end_index)
-        self._pointer.start_index = end
+        self._pointer.end_index = end
 
     # @classmethod
     # def from_language(

pangocffi/rectangle.py

@@ -10,13 +10,26 @@ class Rectangle:
     """
     def __init__(
             self,
-            pointer: Optional[ffi.CData] = None
+            pointer: Optional[ffi.CData] = None,
+            width: Optional[int] = None,
+            height: Optional[int] = None,
+            x: Optional[int] = None,
+            y: Optional[int] = None
     ):
         if pointer is None:
             self.pointer = ffi.new("PangoRectangle *")
         else:
             self.pointer = pointer
 
+        if width is not None:
+            self.pointer.width = width
+        if height is not None:
+            self.pointer.height = height
+        if x is not None:
+            self.pointer.x = x
+        if y is not None:
+            self.pointer.y = y
+
     def get_pointer(self) -> ffi.CData:
         """
         Returns a pointer to the :class:`Rectangle`.
@@ -47,6 +60,14 @@ def x(self) -> int:
         """
         return self.pointer.x
 
+    @x.setter
+    def x(self, value: int):
+        """
+        :param value:
+            Sets the X coordinate of the left side of the rectangle.
+        """
+        self.pointer.x = value
+
     @property
     def y(self) -> int:
         """
@@ -56,6 +77,14 @@ def y(self) -> int:
         """
         return self.pointer.y
 
+    @y.setter
+    def y(self, value: int):
+        """
+        :param value:
+            Sets the Y coordinate of the the top side of the rectangle.
+        """
+        self.pointer.y = value
+
     @property
     def width(self) -> int:
         """
@@ -65,6 +94,14 @@ def width(self) -> int:
         """
         return self.pointer.width
 
+    @width.setter
+    def width(self, value: int):
+        """
+        :param value:
+            Sets the width of the rectangle.
+        """
+        self.pointer.width = value
+
     @property
     def height(self) -> int:
         """
@@ -73,3 +110,11 @@ def height(self) -> int:
         :type: int
         """
         return self.pointer.height
+
+    @height.setter
+    def height(self, value: int):
+        """
+        :param value:
+            Sets the height of the rectangle.
+        """
+        self.pointer.height = value

tests/acceptance/__init__.py

@@ -0,0 +1,124 @@
+import pangocffi
+from pangocffi import Layout, AttrList, Attribute, Underline, Rectangle, Style
+from tests.context_creator import ContextCreator
+
+
+def test_attributes():
+    width = 150
+    height = 50
+    # CFFIs and Contexts
+    context_creator = ContextCreator.create_pdf(
+        'tests/acceptance/output/attributes.pdf', width, height
+    )
+    pangocairo = context_creator.pangocairo
+    cairo_context = context_creator.cairo_context
+
+    text = 'Hi from Παν語! This test is to make sure that text is correctly ' \
+           'annotated, and to also highlight functionality that is not ' \
+           'available from methods like pango.set_markup(\'...\'). ' \
+           'For instance, Attribute.from_shape() allows you to embed a ' \
+           'picture or a widget in a layout. Example: Ø.'
+    text_utf8 = text.encode('utf-8')
+
+    # Using pangocairocffi, this would be `pangocairocffi.create_layout()` with
+    # a cairocffi context object.
+    layout = Layout.from_pointer(
+        pangocairo.pango_cairo_create_layout(cairo_context)
+    )
+
+    layout.set_width(pangocffi.units_from_double(width * 72 / 25.4))
+    layout.set_text(text)
+
+    attr_list = AttrList()
+
+    # Example: Handling byte indexes correctly.
+    # When handling byte indexes, make sure to always use UTF-8 byte strings.
+    # For example , while the string '語' has a length of 1 character in
+    # python, in a UTF-8 byte string this is 3 bytes: `0xe8 0xaa 0x9e`. Pango
+    # will not like byte indexes that occur in the middle of a character.
+    text_to_match = 'Παν語!'.encode('utf-8')
+    match_index = text_utf8.index(text_to_match)
+    match_index_end = match_index + len(text_to_match)
+    attr_list.insert(Attribute.from_style(
+        Style.ITALIC,
+        match_index,
+        match_index_end
+    ))
+
+    # Example: Color alpha
+    # `set_markup()` doesn't appear to have the ability to control color
+    # alphas, but it is supported by Attributes! Note that the alpha color for
+    # underline and foreground text cannot be controlled separately.
+    text_to_match = 'correctly'.encode('utf-8')
+    match_index = text_utf8.index(text_to_match)
+    match_index_end = match_index + len(text_to_match)
+    attr_list.insert(Attribute.from_underline(
+        Underline.ERROR, match_index, match_index_end
+    ))
+    attr_list.insert(Attribute.from_foreground_color(
+        65535, 0, 0, match_index, match_index_end
+    ))
+    attr_list.insert(Attribute.from_underline_color(
+        0, 0, 65535, match_index, match_index_end
+    ))
+    attr_list.insert(Attribute.from_background_color(
+        0, 65535, 0, match_index, match_index_end
+    ))
+    attr_list.insert(Attribute.from_foreground_alpha(
+        32768, match_index, match_index_end
+    ))
+    attr_list.insert(Attribute.from_background_alpha(
+        8192, match_index, match_index_end
+    ))
+
+    # Example: Highlight multiple Monospace texts
+    markup_texts = ('pango.set_markup(\'...\')', 'Attribute.from_shape()')
+    for markup_text in markup_texts:
+        text_to_match = markup_text.encode('utf-8')
+        match_index = text_utf8.index(text_to_match)
+        match_index_end = match_index + len(text_to_match)
+        attr_list.insert(Attribute.from_family(
+            'monospace',
+            match_index,
+            match_index_end
+        ))
+
+    # Example: Shape placeholders
+    # `Attribute.from_shape()` can be used to insert a box within the layout.
+    # In this case, we're inserting a 1cm square that sits on the baseline of
+    # the final line. Note the negative y coordinate of the rectangle.
+    # Visually, the background color will appear a bit larger, that's because
+    # it will also apply a background below the baseline of the font.
+    # Once rendered, it should be possible to retrieve the position of the
+    # shape using using LayoutIter so that an actual image can be rendered in
+    # place should you need to.
+    text_to_match = 'Ø'.encode('utf-8')
+    match_index = text_utf8.index(text_to_match)
+    match_index_end = match_index + len(text_to_match)
+    glyph_length = pangocffi.units_from_double(10 * 72 / 25.4)  # 10 mm
+    ink = Rectangle(
+        width=glyph_length, height=glyph_length, x=0, y=-glyph_length
+    )
+    logical = Rectangle(
+        width=glyph_length, height=glyph_length, x=0, y=-glyph_length
+    )
+    attr_list.insert(Attribute.from_background_color(
+        65535, 0, 0, match_index, match_index_end
+    ))
+    attr_list.insert(Attribute.from_background_alpha(
+        8192, match_index, match_index_end
+    ))
+    attr_list.insert(Attribute.from_shape(
+        ink,
+        logical,
+        match_index,
+        match_index_end
+    ))
+
+    # Apply all the attributes to the layout
+    layout.set_attributes(attr_list)
+
+    # Using pangocairocffi, this would be `pangocairocffi.show_layout(layout)`
+    pangocairo.pango_cairo_show_layout(cairo_context, layout.get_pointer())
+
+    context_creator.close()