feat: add SlidePlaceholder class and implement placeholders property in Slide class

Author: ya7010

src/tppt/_pptx/placeholder.py

@@ -0,0 +1,17 @@
+from typing import Self
+
+from pptx.shapes.placeholder import SlidePlaceholder as PptxSlidePlaceholder
+
+from tppt._pptx.presentation import PptxConvertible
+
+
+class SlidePlaceholder(PptxConvertible[PptxSlidePlaceholder]):
+    def __init__(self, pptx_obj: PptxSlidePlaceholder) -> None:
+        self._pptx = pptx_obj
+
+    def to_pptx(self) -> PptxSlidePlaceholder:
+        return self._pptx
+
+    @classmethod
+    def from_pptx(cls, pptx_obj: PptxSlidePlaceholder) -> Self:
+        return cls(pptx_obj)

src/tppt/_pptx/slide.py

@@ -5,6 +5,8 @@
 
 from pptx.slide import Slide as PptxSlide
 from pptx.slide import SlideLayout as PptxSlideLayout
+
+from tppt._pptx.placeholder import SlidePlaceholder
 from tppt.exception import SlideLayoutIndexError
 from tppt.types import FilePath
 
@@ -34,10 +36,21 @@ def shapes(self) -> list[Shape]:
     @property
     def title(self) -> Title | None:
         """Get slide title shape."""
+
         if title := self._pptx.shapes.title:
             return Title(title)
         return None
 
+    @property
+    def placeholders(self) -> list[SlidePlaceholder]:
+        """Get all placeholders in the slide."""
+        return [
+            SlidePlaceholder(
+                placeholder,  # type: ignore
+            )
+            for placeholder in self._pptx.placeholders
+        ]
+
     def to_pptx(self) -> PptxSlide:
         """Convert to pptx slide."""
         return cast(PptxSlide, self._pptx)

tests/test_slide.py

@@ -0,0 +1,40 @@
+"""Tests for slide module."""
+
+import pytest
+
+import tppt
+from tppt._pptx.placeholder import SlidePlaceholder
+
+
+def test_slide_placeholders() -> None:
+    """Test getting placeholders from a slide."""
+    # Create a presentation with a slide
+    presentation = (
+        tppt.Presentation.builder()
+        .slide(
+            tppt.SlideBuilder(0)  # Use layout 0 which usually has placeholders
+        )
+        .build()
+    )
+
+    # Get the slide from the presentation's pptx object
+    pptx_presentation = presentation.to_pptx()
+    if not pptx_presentation.slides:
+        pytest.skip("No slides in presentation")
+
+    slide = tppt.Slide(pptx_presentation.slides[0])
+
+    # Test that we can get placeholders
+    placeholders = slide.placeholders
+
+    # Check that placeholders is a list
+    assert isinstance(placeholders, list)
+    assert len(placeholders) != 0
+
+    # Verify each placeholder is a SlidePlaceholder instance
+    for placeholder in placeholders:
+        assert isinstance(placeholder, SlidePlaceholder)
+
+        # Check that we can convert it to pptx object
+        pptx_placeholder = placeholder.to_pptx()
+        assert pptx_placeholder is not None