PPTX: shapes with text discard fill color (TextBox vs Shape branch)

[developer0hye]

Description

When a PPTX shape has both a solid fill (or gradient) AND text content, the parser emits it as a TextBox and discards the fill color, stroke, rotation, opacity, and shadow. This causes shapes with background colors and text to lose their background.

Root Cause

In crates/office2pdf/src/parser/pptx.rs (line ~2068-2111), the shape finalization logic is:

let has_text = paragraphs.iter().any(|p| !p.runs.is_empty());

if has_text {
    // TextBox — only text content, fill/stroke/etc. discarded
    kind: FixedElementKind::TextBox(blocks),
} else if let Some(ref geom) = prst_geom {
    // Shape — fill, stroke, rotation preserved
    kind: FixedElementKind::Shape(Shape { fill: shape_fill, ... }),
}

The TextBox branch does not carry any shape properties. So a rectangle with solidFill="#003366" and text "Section Title" inside it will render as plain text with no background.

Expected

A colored rectangle with text overlaid on it.

Actual

Only the text is rendered, with no background shape.

Fix Suggestion

Either:

1. Extend FixedElementKind::TextBox to carry optional shape properties (fill, stroke, etc.), or
2. Emit both a Shape element and a TextBox element at the same position when a shape has both fill and text