Doc: Add alternate text for images in Qt GUI

Alternate text (alt text) improves the documentation experience for
screen readers and for other accessibility tools.

Task-number: QTBUG-135098
Change-Id: Ia5d70756095824f4d3a066c447d43709ab4f6ae2
Reviewed-by: David Boddie <david.boddie@qt.io>
(cherry picked from commit 4098e2d)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

Author: jepasionQt

src/gui/doc/qtgui.qdocconf

@@ -88,4 +88,5 @@ macro.svgcolor.HTML = "<div style=\"padding:10px;color:#fff;background:\1;\"></d
 macro.svgcolor.DocBook = "<db:phrase role=\"color:\1\">&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</db:phrase>"
 
 # Enforce zero documentation warnings
+reportmissingalttextforimages = true
 warninglimit = 0

src/gui/doc/src/coordsys.qdoc

@@ -42,7 +42,9 @@
     \table
     \row
     \li \inlineimage coordinatesystem-rect.svg
+                     {Rectangle on coordinate grid from (1,2) to (7,6)}
     \li \inlineimage coordinatesystem-line.svg
+                     {Line on coordinate grid from (2,7) to (6,1)}
     \row
     \li QRect(QPoint(1, 2), QPoint(7, 6))
     \li QLine(QPoint(2, 7), QPoint(6, 1))
@@ -74,7 +76,9 @@
     \table
     \row
     \li \inlineimage coordinatesystem-rect-raster.svg
+                     {Aliased rectangle with pixels rendered right and below}
     \li \inlineimage coordinatesystem-line-raster.svg
+                     {Aliased line with pixels rendered right and below}
 
     \row
     \li
@@ -96,13 +100,17 @@
     \li {2,1} QRectF
     \row
     \li \inlineimage qrect-diagram-zero.png
+                     {Rectangle showing width() and height() dimensions}
     \li \inlineimage qrectf-diagram-one.png
+                     {Rectangle with one-pixel pen showing corner coordinates}
     \row
     \li Logical representation
     \li One pixel wide pen
     \row
     \li \inlineimage qrectf-diagram-two.png
+                     {Rectangle with two-pixel pen showing corner coordinates}
     \li \inlineimage qrectf-diagram-three.png
+                     {Rectangle with three-pixel pen showing corner coordinates}
     \row
     \li Two pixel wide pen
     \li Three pixel wide pen
@@ -140,7 +148,9 @@
     \table
     \row
     \li \inlineimage coordinatesystem-rect-antialias.svg
+                     {Anti-aliased rectangle with symmetric pixel rendering}
     \li \inlineimage coordinatesystem-line-antialias.svg
+                     {Anti-aliased line with symmetric pixel rendering}
     \row
     \li
 
@@ -164,10 +174,10 @@
 
     \table
     \row
-    \li \inlineimage qpainter-clock.png
-    \li \inlineimage qpainter-rotation.png
-    \li \inlineimage qpainter-scale.png
-    \li \inlineimage qpainter-translation.png
+    \li \inlineimage qpainter-clock.png {Clock without transformation}
+    \li \inlineimage qpainter-rotation.png {Clock with rotation applied}
+    \li \inlineimage qpainter-scale.png {Clock with scale applied}
+    \li \inlineimage qpainter-translation.png {Clock with translation applied}
     \row
     \li nop
     \li \l {QPainter::rotate()}{rotate()}
@@ -200,6 +210,7 @@
     \li {2,1} Analog Clock Example
     \row
     \li \inlineimage coordinatesystem-analogclock.png
+                     {Analog clock widget showing hour and minute hands}
     \li
     The Analog Clock example shows how to draw the contents of a
     custom widget using QPainter's transformation matrix.

src/gui/doc/src/richtext.qdoc

@@ -105,6 +105,7 @@
     \table
     \row
     \li \inlineimage richtext-document.png
+                     {Document structure with frames and text blocks}
     \li \b{Basic structure}
 
     The "top level" of a document might be populated in the way shown.

src/gui/image/qimage.cpp

@@ -502,6 +502,7 @@ bool QImageData::checkForAlphaPixels() const
     \li {2,1}32-bit
     \row
     \li \inlineimage qimage-32bit_scaled.png
+                     {3x3 pixel grid with ARGB color values}
     \li
     \snippet code/src_gui_image_qimage.cpp 0
     \endtable
@@ -523,6 +524,7 @@ bool QImageData::checkForAlphaPixels() const
     \li {2,1} 8-bit
     \row
     \li \inlineimage qimage-8bit_scaled.png
+                     {3x3 pixel grid with indexed colors and color table}
     \li
     \snippet code/src_gui_image_qimage.cpp 1
     \endtable

src/gui/image/qpixmap.cpp

@@ -999,7 +999,7 @@ bool QPixmap::convertFromImage(const QImage &image, Qt::ImageConversionFlags fla
     transformation modes specified by \a aspectRatioMode and \a
     transformMode.
 
-    \image qimage-scaling.png
+    \image qimage-scaling.png {Three aspect ratio modes compared}
 
     \list
     \li If \a aspectRatioMode is Qt::IgnoreAspectRatio, the pixmap

src/gui/kernel/qcursor.cpp

@@ -70,41 +70,41 @@ QT_BEGIN_NAMESPACE
     \table
     \header \li Shape \li Qt::CursorShape Value \li Cursor Name
             \li Shape \li Qt::CursorShape Value \li Cursor Name
-    \row \li \inlineimage cursor-arrow.png
+    \row \li \inlineimage cursor-arrow.png {Arrow cursor}
          \li Qt::ArrowCursor   \li \c left_ptr
-         \li \inlineimage      cursor-sizev.png
+         \li \inlineimage cursor-sizev.png {Vertical resize cursor}
          \li Qt::SizeVerCursor \li \c size_ver
-    \row \li \inlineimage      cursor-uparrow.png
+    \row \li \inlineimage cursor-uparrow.png {Up arrow cursor}
          \li Qt::UpArrowCursor \li \c up_arrow
-         \li \inlineimage      cursor-sizeh.png
+         \li \inlineimage cursor-sizeh.png {Horizontal resize cursor}
          \li Qt::SizeHorCursor \li \c size_hor
-    \row \li \inlineimage      cursor-cross.png
+    \row \li \inlineimage cursor-cross.png {Cross cursor}
          \li Qt::CrossCursor   \li \c cross
-         \li \inlineimage      cursor-sizeb.png
+         \li \inlineimage cursor-sizeb.png {Diagonal resize cursor}
          \li Qt::SizeBDiagCursor \li \c size_bdiag
-    \row \li \inlineimage      cursor-ibeam.png
+    \row \li \inlineimage cursor-ibeam.png {I-beam cursor}
          \li Qt::IBeamCursor   \li \c ibeam
-         \li \inlineimage      cursor-sizef.png
+         \li \inlineimage cursor-sizef.png {Diagonal resize cursor}
          \li Qt::SizeFDiagCursor \li \c size_fdiag
-    \row \li \inlineimage      cursor-wait.png
+    \row \li \inlineimage cursor-wait.png {Wait cursor}
          \li Qt::WaitCursor    \li \c wait
-         \li \inlineimage      cursor-sizeall.png
+         \li \inlineimage cursor-sizeall.png {Move cursor}
          \li Qt::SizeAllCursor \li \c size_all
-    \row \li \inlineimage      cursor-busy.png
+    \row \li \inlineimage cursor-busy.png {Busy cursor}
          \li Qt::BusyCursor    \li \c left_ptr_watch
-         \li \inlineimage      cursor-vsplit.png
+         \li \inlineimage cursor-vsplit.png {Vertical split cursor}
          \li Qt::SplitVCursor  \li \c split_v
-    \row \li \inlineimage      cursor-forbidden.png
+    \row \li \inlineimage cursor-forbidden.png {Forbidden cursor}
          \li Qt::ForbiddenCursor \li \c forbidden
-         \li \inlineimage      cursor-hsplit.png
+         \li \inlineimage cursor-hsplit.png {Horizontal split cursor}
          \li Qt::SplitHCursor  \li \c split_h
-    \row \li \inlineimage      cursor-hand.png
+    \row \li \inlineimage cursor-hand.png {Pointing hand cursor}
          \li Qt::PointingHandCursor \li \c pointing_hand
-         \li \inlineimage      cursor-openhand.png
+         \li \inlineimage cursor-openhand.png {Open hand cursor}
          \li Qt::OpenHandCursor  \li \c openhand
-    \row \li \inlineimage      cursor-whatsthis.png
+    \row \li \inlineimage cursor-whatsthis.png {What's this cursor}
          \li Qt::WhatsThisCursor \li \c whats_this
-         \li \inlineimage      cursor-closedhand.png
+         \li \inlineimage cursor-closedhand.png {Closed hand cursor}
          \li Qt::ClosedHandCursor \li \c closedhand
     \row \li
          \li Qt::DragMoveCursor      \li \c dnd-move or \c move

src/gui/painting/qbrush.cpp

@@ -313,7 +313,8 @@ void QBrushDataPointerDeleter::operator()(QBrushData *d) const noexcept
 
     \table 100%
     \row
-    \li \inlineimage brush-outline.png Outlines
+    \li \inlineimage brush-outline.png
+                     {Two overlapping rectangles with outlines}
     \li
 
     To specify the style and color of lines and outlines, use the
@@ -1283,7 +1284,6 @@ QDataStream &operator>>(QDataStream &s, QBrush &b)
  * QGradient implementations
  */
 
-
 /*!
     \class QGradient
     \ingroup painting
@@ -1313,9 +1313,11 @@ QDataStream &operator>>(QDataStream &s, QBrush &b)
     \li QRadialGradient
     \li QConicalGradient
     \row
-    \li \inlineimage qgradient-linear.png
+    \li \inlineimage qgradient-linear.png {Linear gradient from white to blue}
     \li \inlineimage qgradient-radial.png
+                     {Radial gradient from white center to blue}
     \li \inlineimage qgradient-conical.png
+                     {Conical gradient sweeping around center}
     \endtable
 
     The colors in a gradient are defined using stop points of the
@@ -1351,8 +1353,11 @@ QDataStream &operator>>(QDataStream &s, QBrush &b)
     \table
     \row
     \li \inlineimage qradialgradient-pad.png
+                     {Radial gradient with pad spread}
     \li \inlineimage qradialgradient-repeat.png
+                     {Radial gradient with repeat spread}
     \li \inlineimage qradialgradient-reflect.png
+                     {Radial gradient with reflect spread}
     \row
     \li \l {QGradient::PadSpread}{PadSpread}
     \li \l {QGradient::RepeatSpread}{RepeatSpread}
@@ -1883,9 +1888,11 @@ bool QGradient::operator==(const QGradient &gradient) const
 
     \table
     \row
-    \li \inlineimage qlineargradient-pad.png
+    \li \inlineimage qlineargradient-pad.png {Linear gradient with pad spread}
     \li \inlineimage qlineargradient-reflect.png
+                     {Linear gradient with reflect spread}
     \li \inlineimage qlineargradient-repeat.png
+                     {Linear gradient with repeat spread}
     \row
     \li \l {QGradient::PadSpread}{PadSpread} (default)
     \li \l {QGradient::ReflectSpread}{ReflectSpread}
@@ -1909,7 +1916,6 @@ bool QGradient::operator==(const QGradient &gradient) const
     Gradients Example}
 */
 
-
 /*!
     Constructs a default linear gradient with interpolation area
     between (0, 0) and (1, 1).
@@ -2048,7 +2054,6 @@ void QLinearGradient::setFinalStop(const QPointF &stop)
     m_data.linear.y2 = stop.y();
 }
 
-
 /*!
     \class QRadialGradient
     \ingroup painting
@@ -2072,8 +2077,11 @@ void QLinearGradient::setFinalStop(const QPointF &stop)
     \table
     \row
     \li \inlineimage qradialgradient-pad.png
+                     {Radial gradient with pad spread}
     \li \inlineimage qradialgradient-reflect.png
+                     {Radial gradient with reflect spread}
     \li \inlineimage qradialgradient-repeat.png
+                     {Radial gradient with repeat spread}
     \row
     \li \l {QGradient::PadSpread}{PadSpread} (default)
     \li \l {QGradient::ReflectSpread}{ReflectSpread}

src/gui/painting/qcolor.cpp

@@ -558,9 +558,9 @@ static bool qColorCheckCmykFValidity(float c, float m, float y, float k, float a
     \header
     \li RGB \li HSV \li CMYK
     \row
-    \li \inlineimage qcolor-rgb.png
-    \li \inlineimage qcolor-hsv.png
-    \li \inlineimage qcolor-cmyk.png
+    \li \inlineimage qcolor-rgb.png {Color wheel with RGB values}
+    \li \inlineimage qcolor-hsv.png {Color wheel with HSV values}
+    \li \inlineimage qcolor-cmyk.png {Color wheel with CMYK values}
     \endtable
 
     The QColor constructor creates the color based on RGB values.  To
@@ -703,19 +703,19 @@ static bool qColorCheckCmykFValidity(float c, float m, float y, float k, float a
     color wheel familiar to most people. Red is 0 (degrees), green is
     120, and blue is 240.
 
-    \inlineimage qcolor-hue.png
+    \inlineimage qcolor-hue.png {Color wheel showing hue values from 0 to 300}
 
     \li S, for saturation, is in the range 0 to 255, and the bigger it is,
     the stronger the color is. Grayish colors have saturation near 0; very
     strong colors have saturation near 255.
 
-    \inlineimage qcolor-saturation.png
+    \inlineimage qcolor-saturation.png {Saturation gradient from gray to blue}
 
     \li V, for value, is in the range 0 to 255 and represents lightness or
     brightness of the color. 0 is black; 255 is as far from black as
     possible.
 
-    \inlineimage qcolor-value.png
+    \inlineimage qcolor-value.png {Value gradient from black to white}
     \endlist
 
     Here are some examples: pure red is H=0, S=255, V=255; a dark red,