From 011794130c8e4bb64dbc3c8c9b50849b278cdda3 Mon Sep 17 00:00:00 2001
From: Alexander Volkov <a.volkov@rusbitech.ru>
Date: Thu, 28 Mar 2019 13:59:35 +0300
Subject: Forward physical parameters for derived QImages
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More specifically, for masks and rotated images.
Add tests for it, also add tests that image metadata is
forwarded for converted and copied images.

Fixes: QTBUG-49259
Change-Id: I05d4a468b17f53a2625500b871c01b2c53b981a1
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
---
 src/gui/image/qimage.cpp | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

(limited to 'src/gui/image/qimage.cpp')

diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index 3e18ca6528..ed6f23ee56 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -1089,15 +1089,31 @@ void QImage::detach()
 }
 
 
-static void copyMetadata(QImageData *dst, const QImageData *src)
+static void copyPhysicalMetadata(QImageData *dst, const QImageData *src)
 {
-    // Doesn't copy colortable and alpha_clut, or offset.
     dst->dpmx = src->dpmx;
     dst->dpmy = src->dpmy;
     dst->devicePixelRatio = src->devicePixelRatio;
+}
+
+static void copyMetadata(QImageData *dst, const QImageData *src)
+{
+    // Doesn't copy colortable and alpha_clut, or offset.
+    copyPhysicalMetadata(dst, src);
     dst->text = src->text;
 }
 
+static void copyMetadata(QImage *dst, const QImage &src)
+{
+    dst->setDotsPerMeterX(src.dotsPerMeterX());
+    dst->setDotsPerMeterY(src.dotsPerMeterY());
+    dst->setDevicePixelRatio(src.devicePixelRatio());
+    const auto textKeys = src.textKeys();
+    for (const auto &key: textKeys)
+        dst->setText(key, src.text(key));
+
+}
+
 /*!
     \fn QImage QImage::copy(int x, int y, int width, int height) const
     \overload
@@ -2924,8 +2940,10 @@ QImage QImage::createAlphaMask(Qt::ImageConversionFlags flags) const
     }
 
     QImage mask(d->width, d->height, Format_MonoLSB);
-    if (!mask.isNull())
+    if (!mask.isNull()) {
         dither_to_Mono(mask.d, d, flags, true);
+        copyPhysicalMetadata(mask.d, d);
+    }
     return mask;
 }
 
@@ -3043,6 +3061,7 @@ QImage QImage::createHeuristicMask(bool clipTight) const
 
 #undef PIX
 
+    copyPhysicalMetadata(m.d, d);
     return m;
 }
 #endif //QT_NO_IMAGE_HEURISTIC_MASK
@@ -3086,6 +3105,8 @@ QImage QImage::createMaskFromColor(QRgb color, Qt::MaskMode mode) const
     }
     if  (mode == Qt::MaskOutColor)
         maskImage.invertPixels();
+
+    copyPhysicalMetadata(maskImage.d, d);
     return maskImage;
 }
 
@@ -4655,8 +4676,7 @@ QImage QImage::smoothScaled(int w, int h) const {
 static QImage rotated90(const QImage &image)
 {
     QImage out(image.height(), image.width(), image.format());
-    out.setDotsPerMeterX(image.dotsPerMeterY());
-    out.setDotsPerMeterY(image.dotsPerMeterX());
+    copyMetadata(&out, image);
     if (image.colorCount() > 0)
         out.setColorTable(image.colorTable());
     int w = image.width();
@@ -4684,8 +4704,7 @@ static QImage rotated180(const QImage &image)
         return image.mirrored(true, true);
 
     QImage out(image.width(), image.height(), image.format());
-    out.setDotsPerMeterX(image.dotsPerMeterY());
-    out.setDotsPerMeterY(image.dotsPerMeterX());
+    copyMetadata(&out, image);
     if (image.colorCount() > 0)
         out.setColorTable(image.colorTable());
     int w = image.width();
@@ -4697,8 +4716,7 @@ static QImage rotated180(const QImage &image)
 static QImage rotated270(const QImage &image)
 {
     QImage out(image.height(), image.width(), image.format());
-    out.setDotsPerMeterX(image.dotsPerMeterY());
-    out.setDotsPerMeterY(image.dotsPerMeterX());
+    copyMetadata(&out, image);
     if (image.colorCount() > 0)
         out.setColorTable(image.colorTable());
     int w = image.width();
-- 
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