Qt技术问题：如何确定QTextEdit中富文本的最小尺寸

Absolutely, you can pull this off! The core problem you're hitting is that the QTextDocument inside your QTextEdit hasn't run its layout calculations yet before the widget is shown—hence those zero values from size() and idealWidth(). The trick is to manually trigger the document's layout process, even when the widget is still hidden.

Here's a step-by-step solution tailored to your code:

1. After setting up all your text content (including setHtml(), append(), and alignment calls), add this code to calculate the minimum required size:

   // Grab the text document from your QTextEdit
   QTextDocument* doc = textEdit->document();
   
   // Sync the document's default font with the QTextEdit's font
   // This ensures layout matches what will actually be displayed
   doc->setDefaultFont(textEdit->font());
   
   // Tell the document to calculate its ideal width (no forced wrapping)
   // Since you're using <br> for line breaks, this will respect your fixed lines
   doc->setTextWidth(-1);
   
   // Force the document to compute its full size
   doc->adjustSize();
   
   // Get the document's content size
   QSize docContentSize = doc->size().toSize();
   
   // Add the QTextEdit's internal margins (borders/padding) to get the total minimum size
   QMargins widgetMargins = textEdit->contentsMargins();
   textEdit->setMinimumSize(
       docContentSize.width() + widgetMargins.left() + widgetMargins.right(),
       docContentSize.height() + widgetMargins.top() + widgetMargins.bottom()
   );
   

Why this works: #

• By syncing the font, we make sure the layout uses the same typography as your final QTextEdit (critical since your HTML specifies Courier New).
• setTextWidth(-1) tells the document to use the natural width of its content (no wrapping) instead of a fixed viewport width.
• adjustSize() forces the document to run its layout engine immediately, even without the widget being visible, so size() returns the real dimensions of your text content.
• We add the widget's margins because those are part of the QTextEdit's total footprint, not just the text content.

Quick notes: #

• If you later modify the text in the QTextEdit, you'll need to re-run this calculation to update the minimum size.
• This works perfectly with your hard-coded line breaks (<br>). If you ever switch to automatic wrapping, you'd need to set a specific setTextWidth() value that matches your layout's constraints first.

内容的提问来源于stack exchange，提问作者so.very.tired