From 1471f2ae0924e5d124178d1953a14db889348da0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Morten=20Johan=20S=C3=B8rvig?= <morten.sorvig@qt.io>
Date: Sun, 21 Feb 2021 20:46:22 +0100
Subject: Add deviceIndependentSize() to QPixmap and QImage

This function returns the size in device independent
pixels, and should be used when calculating user
interface sizes.


Change-Id: I528123f962595a3da42438ca560289a29aca4917
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
---
 src/gui/image/qimage.cpp  | 20 ++++++++++++++++++--
 src/gui/image/qimage.h    |  1 +
 src/gui/image/qpixmap.cpp | 17 ++++++++++++++++-
 src/gui/image/qpixmap.h   |  1 +
 4 files changed, 36 insertions(+), 3 deletions(-)

(limited to 'src/gui')

diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index 33c12993d7..fadfd5be73 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -1316,7 +1316,7 @@ int QImage::height() const
 
     Returns the size of the image, i.e. its width() and height().
 
-    \sa {QImage#Image Information}{Image Information}
+    \sa {QImage#Image Information}{Image Information}, deviceIndependentSize()
 */
 QSize QImage::size() const
 {
@@ -1449,7 +1449,7 @@ qreal QImage::devicePixelRatio() const
     high-DPI image rather than a large image
     (see \l{Drawing High Resolution Versions of Pixmaps and Images}).
 
-    \sa devicePixelRatio()
+    \sa devicePixelRatio(), deviceIndependentSize()
 */
 void QImage::setDevicePixelRatio(qreal scaleFactor)
 {
@@ -1464,6 +1464,22 @@ void QImage::setDevicePixelRatio(qreal scaleFactor)
         d->devicePixelRatio = scaleFactor;
 }
 
+/*!
+    Returns the size of the pixmap in device independent pixels.
+
+    This value should be used when using the pixmap size in user interface
+    size calculations.
+
+    The return value is equivalent to pixmap.size() / pixmap.devicePixelRatio(),
+*/
+QSizeF QImage::deviceIndependentSize() const
+{
+    if (!d)
+        return QSizeF(0, 0);
+    return QSizeF(d->width, d->height) / d->devicePixelRatio;
+}
+
+
 /*!
     \since 5.10
     Returns the image data size in bytes.
diff --git a/src/gui/image/qimage.h b/src/gui/image/qimage.h
index ae63c758f4..59e07e7dd0 100644
--- a/src/gui/image/qimage.h
+++ b/src/gui/image/qimage.h
@@ -219,6 +219,7 @@ public:
 
     qreal devicePixelRatio() const;
     void setDevicePixelRatio(qreal scaleFactor);
+    QSizeF deviceIndependentSize() const;
 
     void fill(uint pixel);
     void fill(const QColor &color);
diff --git a/src/gui/image/qpixmap.cpp b/src/gui/image/qpixmap.cpp
index d8473001aa..2f9c4fd617 100644
--- a/src/gui/image/qpixmap.cpp
+++ b/src/gui/image/qpixmap.cpp
@@ -633,7 +633,7 @@ qreal QPixmap::devicePixelRatio() const
     high-DPI pixmap rather than a large pixmap
     (see \l{Drawing High Resolution Versions of Pixmaps and Images}).
 
-    \sa devicePixelRatio()
+    \sa devicePixelRatio(), devicePixelSize()
 */
 void QPixmap::setDevicePixelRatio(qreal scaleFactor)
 {
@@ -647,6 +647,21 @@ void QPixmap::setDevicePixelRatio(qreal scaleFactor)
     data->setDevicePixelRatio(scaleFactor);
 }
 
+/*!
+    Returns the size of the pixmap in device independent pixels.
+
+    This value should be used when using the pixmap size in user interface
+    size calculations.
+
+    The return value is equivalent to pixmap.size() / pixmap.devicePixelRatio(),
+*/
+QSizeF QPixmap::deviceIndependentSize() const
+{
+    if (!data)
+        return QSizeF(0, 0);
+    return QSizeF(data->width(), data->height()) / data->devicePixelRatio();
+}
+
 #ifndef QT_NO_IMAGE_HEURISTIC_MASK
 /*!
     Creates and returns a heuristic mask for this pixmap.
diff --git a/src/gui/image/qpixmap.h b/src/gui/image/qpixmap.h
index 42d4e27102..9d4d8e582d 100644
--- a/src/gui/image/qpixmap.h
+++ b/src/gui/image/qpixmap.h
@@ -101,6 +101,7 @@ public:
 
     qreal devicePixelRatio() const;
     void setDevicePixelRatio(qreal scaleFactor);
+    QSizeF deviceIndependentSize() const;
 
     bool hasAlpha() const;
     bool hasAlphaChannel() const;
-- 
cgit v1.2.3