Fix page breaking with large images

Don't go into an infinite loop breaking pages, when an image is about
as large as the page. Correctly take top and bottom margins into account
when calculating whether the image could fit on one page.

Amends change 416b4cf685.

Fixes: QTBUG-73730
Change-Id: Id311ddf05510be3b1d131702f4e17025a9861e58
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
This commit is contained in:
Lars Knoll 2019-04-26 09:15:52 +02:00
parent 78c84c6353
commit b4cc294347
2 changed files with 64 additions and 1 deletions

View File

@ -145,6 +145,9 @@ struct QTextLayoutStruct {
inline QFixed absoluteY() const
{ return frameY + y; }
inline QFixed contentHeight() const
{ return pageHeight - pageBottomMargin - pageTopMargin; }
inline int currentPage() const
{ return pageHeight == 0 ? 0 : (absoluteY() / pageHeight).truncate(); }
@ -2701,7 +2704,7 @@ void QTextDocumentLayoutPrivate::layoutBlock(const QTextBlock &bl, int blockPosi
getLineHeightParams(blockFormat, line, scaling, &lineAdjustment, &lineBreakHeight, &lineHeight, &lineBottom);
while (layoutStruct->pageHeight > 0 && layoutStruct->absoluteY() + lineBreakHeight > layoutStruct->pageBottom &&
layoutStruct->pageHeight >= lineBreakHeight) {
layoutStruct->contentHeight() >= lineBreakHeight) {
layoutStruct->newPage();
floatMargins(layoutStruct->y, layoutStruct, &left, &right);

View File

@ -59,6 +59,8 @@ private slots:
void imageAtRightAlignedTab();
void blockVisibility();
void largeImage();
private:
QTextDocument *doc;
};
@ -347,5 +349,63 @@ void tst_QTextDocumentLayout::blockVisibility()
QCOMPARE(doc->size(), halfSize);
}
void tst_QTextDocumentLayout::largeImage()
{
auto img = QImage(400, 500, QImage::Format_ARGB32_Premultiplied);
img.fill(Qt::black);
{
QTextDocument document;
document.addResource(QTextDocument::ImageResource,
QUrl("data://test.png"), QVariant(img));
document.setPageSize({500, 504});
auto html = "<img src=\"data://test.png\">";
document.setHtml(html);
QCOMPARE(document.pageCount(), 2);
}
{
QTextDocument document;
document.addResource(QTextDocument::ImageResource,
QUrl("data://test.png"), QVariant(img));
document.setPageSize({500, 508});
auto html = "<img src=\"data://test.png\">";
document.setHtml(html);
QCOMPARE(document.pageCount(), 1);
}
{
QTextDocument document;
document.addResource(QTextDocument::ImageResource,
QUrl("data://test.png"), QVariant(img));
document.setPageSize({585, 250});
auto html = "<img src=\"data://test.png\">";
document.setHtml(html);
QCOMPARE(document.pageCount(), 3);
}
{
QTextDocument document;
document.addResource(QTextDocument::ImageResource,
QUrl("data://test.png"), QVariant(img));
document.setPageSize({585, 258});
auto html = "<img src=\"data://test.png\">";
document.setHtml(html);
QCOMPARE(document.pageCount(), 2);
}
}
QTEST_MAIN(tst_QTextDocumentLayout)
#include "tst_qtextdocumentlayout.moc"