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// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
/*!
\example 3d/widgetgraphgallery
\meta tags {Graphs, Bar Graph, Custom Proxy, Scatter Graph, Custom Input Handler, Surface Graph, QCustom3DItem, Textured Surface}
\examplecategory {Data Visualization}
\title Graph Gallery
\ingroup qtgraphs_examples_3D
\brief Gallery of Bar, Scatter, and Surface graphs.
\e {Graph Gallery} demonstrates all three graph types and some of their special features.
The graphs have their own tabs in the application.
\image widgetgraphgallery-example.png
{3D surface plot with gradient coloring and customization options}
\include examples-run.qdocinc
\section1 Bar Graph
In the \uicontrol {Bar Graph} tab, create a 3D bar graph using Q3DBarWidgetItem and combine
the use of widgets to adjust various bar graph qualities. The example shows how to:
\list
\li Create an application with Q3DBarWidgetItem and some control widgets
\li Use QBar3DSeries and QBarDataProxy to set data to the graph
\li Adjust some graph and series properties using widget controls
\li Select a row or a column by clicking an axis label
\li Create a custom proxy to use with Q3DBarWidgetItem
\endlist
For information about interacting with the graph, see
\l{Qt Graphs Interacting with Data in 3D}{this page}.
\section2 Creating the Application
\list 1
\li In \c{bargraph.cpp}, instantiate QQuickWidget and Q3DBarsWidgetItem,
and set the QQuickWidget instance as the widget for Q3DBarsWidgetItem:
\snippet 3d/widgetgraphgallery/bargraph.cpp creation
\li Create a container widget, and horizontal and vertical layouts. Add
the graph and the vertical layout to the horizontal one:
\snippet 3d/widgetgraphgallery/bargraph.cpp adding to layout
\li Create another class to handle the data addition and other
interaction with the graph:
\snippet 3d/widgetgraphgallery/bargraph.cpp create the data handler
\endlist
\section2 Setting up the Bar Graph
\list 1
\li Set up the graph in the constructor of the \c GraphModifier class:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp set up the graph
\li Create the axes and the series into member variables to support
changing them:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp set up axes
\li Set some visual qualities for the graph:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp adjust visuals
\li Set up the axes and make them the active axes of the graph:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp activate axes
\li Give axis labels a small autorotation angle:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp auto angle
This is done to make them orient slightly toward the camera, which
improves axis label readability at extreme camera angles.
\li Initialize the visual properties of the series. Note that the second
series is initially not visible:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp initialize series visuals
\li Add the series to the graph:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp add series
\li Set the camera angle by calling the same method the camera angle
change button in the UI uses to cycle through various camera angles:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp invoke camera preset
\li The new camera preset is set to the graph:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp change the preset
\endlist
\section2 Adding Data to the Graph
At the end of the constructor, call a method that sets up the data:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp invoke data reset
This method adds data to the relevant series using proxies of the two series:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp set up data
\dots 0
\snippet 3d/widgetgraphgallery/graphmodifier.cpp populate series vie proxies
\section2 Using Widgets to Control the Graph
Continue by adding some widgets in \c{bargraph.cpp}.
\list 1
\li Add a slider:
\snippet 3d/widgetgraphgallery/bargraph.cpp creating a slider
\li Use the slider to rotate the graph instead of just using a mouse or
touch. Add it to the vertical layout:
\snippet 3d/widgetgraphgallery/bargraph.cpp adding the slider
\li Connect it to a method in \c GraphModifier:
\snippet 3d/widgetgraphgallery/bargraph.cpp connecting the slider
\li Create a slot in \c GraphModifier for the signal connection. Specify the
actual camera position along the orbit around the center point, instead
of specifying a preset camera angle:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp rotate camera
\endlist
You can now use the slider to rotate the graph.
Add more widgets to the vertical layout to control:
\list
\li Graph rotation
\li Label style
\li Camera preset
\li Background visibility
\li Grid visibility
\li Bar shading smoothness
\li Visibility of the second bar series
\li Value axis direction
\li Axis title visibility and rotation
\li Data range to be shown
\li Bar style
\li Selection mode
\li Theme
\li Shadow quality
\li Font
\li Font size
\li Axis label rotation
\li Data mode
\endlist
Some widget controls are intentionally disabled when in the \uicontrol {Custom Proxy Data}
data mode.
\section2 Selecting a Row or Column by Clicking an Axis Label
Selection by axis label is default functionality for bar graphs. For example,
you can select rows by clicking an axis label in the following way:
\list 1
\li Change selection mode to \c Row
\li Click a year label
\li The row with the clicked year is selected
\endlist
The same method works with \c Slice and \c Item flags, as long as
either \c Row or \c Column is set as well.
\section2 Zooming to Selection
As an example of adjusting the camera target, implement an animation of zooming to
selection via a button press. Animation initializations are done in the constructor:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp animation setup
Function \c{GraphModifier::zoomToSelectedBar()} contains the zooming functionality.
QPropertyAnimation \c m_animationCameraTarget targets
\l {Q3DGraphsWidgetItem::cameraTargetPosition}{cameraTargetPosition} property,
which takes a value normalized to the range (-1, 1).
Figure out where the selected bar is relative to axes, and use that as the end value for
\c{m_animationCameraTarget}:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp calculate target
\dots 0
\snippet 3d/widgetgraphgallery/graphmodifier.cpp set target
Then, rotate the camera so that it always points approximately to the center of
the graph at the end of the animation:
\snippet 3d/widgetgraphgallery/graphmodifier.cpp center camera
\section2 Model Proxy for Data
When you toggle \uicontrol {Model Proxy Data} data mode on, the graph in
the example uses an item model based dataset and the corresponding proxy.
\section3 RainfallData
Class \c RainfallData sets up a QItemModelBarDataProxy along with the series
and axes.
\list 1
\li We use a \c{std::array<double, 12>} to store the values of a year
indexed by month. The static \c readData() helper function reads
the data, returning a QList of them indexed by year:
\snippet 3d/widgetgraphgallery/rainfalldata.cpp 1
\dots
\li The QList represents a two dimensional array indexed by year and month,
respectively. From this, we populate a QRangeModel and pass it to
a QItemModelBarDataProxy() in the \c RainfallData class:
\snippet 3d/widgetgraphgallery/rainfalldata.cpp 0
\li Finally, add a function for getting the created series for displaying:
\snippet 3d/widgetgraphgallery/rainfalldata.h 0
\endlist
\section1 Scatter Graph
In the \uicontrol {Scatter Graph} tab, create a 3D scatter graph using
Q3DScatterWidgetItem. The example shows how to:
\list
\li Set up Q3DScatterWidgetItem graph
\li Use QScatterDataProxy to set data to the graph
\li Create and add a custom input handler
\endlist
For basic application creation, see \l {Bar Graph}.
\section2 Setting up the Scatter Graph
\list 1
\li Set up some visual qualities for the graph in the constructor of the
\c ScatterDataModifier:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 0
None of these settings are mandatory, but they serve to override graph
defaults. To observe the appearance with the preset defaults, the block
above can be commented out.
\li Create a QScatterDataProxy and the associated QScatter3DSeries. Set a
custom label format and mesh smoothing for the series and add it to the graph:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 1
\endlist
\section2 Adding Scatter Data
\list 1
\li In the \c ScatterDataModifier constructor, add data to the graph:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 2
\li The actual data addition is done in \c addData() method. First, configure the axes:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 3
You could do this also in the constructor of \c {ScatterDataModifier}. Doing it here
keeps the constructor simpler and the axes' configuration near the data.
\li Create a data array and populate it:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 4
\dots
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 5
\li Finally, tell the proxy to start using the data we gave it:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 6
\endlist
Now, the graph has the data and is ready for use. For information about adding widgets
to control the graph, see \l {Using Widgets to Control the Graph}.
\section2 Replacing Default Input Handling
To replace the default input handling mechanism, set the new input handlers of
Q3DScatterWidgetItem, which implements the custom behavior:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 8
\section2 Extending Mouse Event Handling
Implement a new \c{drag} event handler. It provides a mouse movement distance
for the axis dragging calculation (see
\l {Implementing Axis Dragging} for details):
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 8
\section2 Implementing Axis Dragging
\list 1
\li Start listening to the selection signal from the graph. Do that in the
constructor, and connect it to the \c handleElementSelected method:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 8
\li In \c {handleElementSelected}, check the type of the selection, and set
the internal state based on it:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 9
\li The actual dragging logic is implemented in the \c handleAxisDragging
method, which is called from \c {drag} event:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 10
\li In \c {handleAxisDragging}, first get the scene orientation from the
active camera:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 11
\li Calculate the modifiers for mouse movement direction based on the
orientation:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 12
\li Calculate the mouse movement, and modify it based on the y rotation of
the camera:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 13
\li Apply the moved distance to the correct axis:
\snippet 3d/widgetgraphgallery/scatterdatamodifier.cpp 14
\endlist
\section1 Surface Graph
In the \uicontrol {Surface Graph} tab, create a 3D surface graph using
Q3DSurfaceWidgetItem. The example shows how to:
\list
\li Set up a basic QSurfaceDataProxy and set data for it.
\li Use QHeightMapSurfaceDataProxy for showing 3D height maps.
\li Use topographic data to create 3D height maps.
\li Use three different selection modes for studying the graph.
\li Use axis ranges to display selected portions of the graph.
\li Set a custom surface gradient.
\li Add custom items and labels with QCustom3DItem and QCustom3DLabel.
\li Use custom input handler to enable zooming and panning.
\li Highlight an area of the surface.
\endlist
For basic application creation, see \l {Bar Graph}.
\section2 Simple Surface with Generated Data
\list 1
\li First, instantiate a new QSurfaceDataProxy and attach it to a new QSurface3DSeries:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 0
\li Fill the proxy with a simple square root and sine wave data. Create a
\c QSurfaceDataArray instance and add \c QSurfaceDataRow elements to it.
Set the created \c QSurfaceDataArray as the data array for the
QSurfaceDataProxy by calling \c{resetArray()}.
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 1
\endlist
\section2 Multiseries Height Map Data
Create the height map by instantiating a QHeightMapSurfaceDataProxy with a
QImage containing the height data. Use QHeightMapSurfaceDataProxy::setValueRanges()
to define the value range of the map. In the example, the map is from an
imaginary position of 34.0\unicode 0x00B0 N - 40.0\unicode 0x00B0 N and
18.0\unicode 0x00B0 E - 24.0\unicode 0x00B0 E. These values are used to
position the map on the axes.
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 2
Add the other surface layers the same way, by creating a proxy and a series
for them using height map images.
-
\section2 Topographic Map Data
The topographic data is obtained from the National Land Survey of Finland.
It provides a product called \c{Elevation Model 2 m}, which is suitable for
this example.
The topography data is from Levi fell. The accuracy of the data is well
beyond the need, and therefore it is compressed and encoded into a PNG file.
The height value of the original ASCII data is encoded into RGB format using
a multiplier, as demonstrated in the code sample below. The multiplier is
calculated by dividing the largest 24-bit value with the highest point in
Finland.
QHeightMapSurfaceDataProxy converts only one-byte values. To utilize the
higher accuracy of the data from the National Land Survey of Finland, read
the data from the PNG file and decode it into a QSurface3DSeries.
\list 1
\li Define the encoding multiplier:
\snippet 3d/widgetgraphgallery/topographicseries.cpp 0
\li Perform the actual decoding:
\snippet 3d/widgetgraphgallery/topographicseries.cpp 1
\endlist
Now, a Surface Graph can consume the data via the proxy.
\section2 Selecting the Data Set
To demonstrate different proxies, the \uicontrol {Surface Graph} has three
radio buttons to switch between the series.
With \uicontrol {Sqrt & Sin}, the simple generated series is activated.
\list 1
\li Set the decorative features, such as enabling the grid for the
surface, and selecting the flat shading mode.
\li Define the axis label format and value ranges. Set automatic label
rotation to improve label readability at low camera angles.
\li Make sure the correct series is added to the graph and the others
are not.
\endlist
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 3
With \uicontrol {Multiseries Height Map}, the height map series are
activated and others are disabled. Auto-adjusting the Y-axis range works
well for the height map surface, so ensure it is set.
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 4
With \uicontrol {Textured Topography}, the topographic series is activated
and others are disabled. Activate a custom input handler for this series,
to be able to highlight areas on it:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 5
See \l {Use Custom Input Handler to Enable Zooming and Panning} for
information about the custom input handler for this data set.
\section2 Selection Modes
The three selection modes supported by Q3DSurfaceWidgetItem can be used with
radio buttons. To activate the selected mode or to clear it, add the
following inline methods:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.h 0
To support doing a slice selection to all visible series
in the graph simultaneously, add \c{QtGraphs3D::SelectionFlag::Slice} and
\c{QtGraphs3D::SelectionFlag::MultiSeries} flags for the row and column
selection modes.
\section2 Axis Ranges for Studying the Graph
The example has four slider controls for adjusting the min and max values
for the X and Z axes. When selecting the proxy, these sliders are adjusted
to match the axis ranges of the current data set:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 6
To add support for setting the X range from the widget controls to the
graph, add:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 7
Add the support for Z range the same way.
\section2 Custom Surface Gradients
With the \uicontrol {Sqrt & Sin} data set, custom surface gradients can be
taken into use with two push buttons. Define the gradient with
QLinearGradient, where the desired colors are set. Also, change the color
style to Q3DTheme::ColorStyle::RangeGradient to use the gradient.
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 8
\section2 Adding Custom Meshes to the Application
To add custom meshes tp the application:
\list
\li \b{For a cmake build}. Add the mesh files to \c{CMakeLists.txt}:
\badcode
set(graphgallery_resource_files
...
"data/oilrig.mesh"
"data/pipe.mesh"
"data/refinery.mesh"
...
)
qt6_add_resources(widgetgraphgallery "widgetgraphgallery"
PREFIX
"/"
FILES
${graphgallery_resource_files}
)
\endcode
\li \b{For a qmake build}. Add the mesh files in the qrc resource file:
\badcode
<RCC>
<qresource prefix="/">
...
<file>data/refinery.mesh</file>
<file>data/oilrig.mesh</file>
<file>data/pipe.mesh</file>
...
</qresource>
</RCC>
\endcode
\endlist
\section2 Adding Custom Item to a Graph
With the \uicontrol {Multiseries Height Map} data set, custom items are
inserted into the graph and can be toggled on or off using checkboxes. Other
visual changes can also be controlled with another set of checkboxes,
including see-through for the two top layers, and a highlight for the bottom
layer.
\list
\li Creating a small QImage. Fill it with a single color to use as the color for the
custom object:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 9
\li Specify the position of the item in a variable. The position can then
be used for removing the correct item from the graph:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 10
\li Create a new QCustom3DItem with all the parameters:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 11
\li Add the item to the graph:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 12
\endlist
\section2 Adding Custom Label to a Graph
Adding a custom label is very similar to adding a custom item. For the
label, a custom mesh is not needed, but just a QCustom3DLabel instance:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 13
\section2 Removing Custom Item from a Graph
To remove a specific item from the graph, call \c removeCustomItemAt() with
the position of the item:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 14
\note Removing a custom item from the graph also deletes the object. To
preserve the item, use the \c releaseCustomItem() method instead.
\section2 Texture to a Surface Series
With the \uicontrol {Textured Topography} data set, create a map texture to
be used with the topographic height map.
Set an image to be used as the texture on a surface with
QSurface3DSeries::setTextureFile(). Add a check box to control if the
texture is set or not, and a handler to react to the checkbox state:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 15
The image in this example is read from a JPG file. Setting an empty file
with the method clears the texture, and the surface uses the gradients or
colors from the theme.
\section2 Use Custom Input Handler to Enable Zooming and Panning
With the \uicontrol {Textured Topography} data set, create a custom input
handler to highlight the selection on the graph and allow panning the graph.
The panning implementation is similar to the one shown in
\l{Implementing Axis Dragging}. The difference is that, in this example, you
only follow the X and Z axes and don't allow dragging the surface outside
the graph. To limit the dragging, follow the limits of the axes and do
nothing if going outside the graph:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 17
For zooming, catch the \c wheelEvent and adjust the X and Y axis ranges
according to the delta value on QWheelEvent. Adjust the Y axis so that the
aspect ratio between the Y axis and the XZ plane stays the same. This
prevents getting a graph in which the height is exaggerated:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 18
Next, add some limits to the zoom level, so that it won't get too near to or
far from the surface. For instance, if the value for the X axis gets below
the allowed limit, that is, zooming gets too far, the value is set to the
minimum allowed value. If the range is going to below the range minimum,
both ends of the axis are adjusted so that the range stays at the limit:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 19
\section2 Highlight an Area of the Surface
To implement a highlight to be displayed on the surface, create a copy of
the series and add some offset to the y value. In this example, the class
\c HighlightSeries implements the creation of the copy in its
\c handlePositionChange method.
First, give \c HighlightSeries the pointer to the original series, and then
start listening to the QSurface3DSeries::selectedPointChanged signal:
\snippet 3d/widgetgraphgallery/highlightseries.cpp 0
When the signal triggers, check that the position is valid. Then, calculate
he ranges for the copied area, and check that they stay within the bounds.
Finally, fill the data array of the highlight series with the range from the
data array of the topography series:
\snippet 3d/widgetgraphgallery/highlightseries.cpp 1
\section2 A Gradient to the Highlight Series
Since the \c HighlightSeries is a QSurface3DSeries, all the decoration
methods a series can have are available. In this example, add a gradient to
emphasize the elevation. Because the suitable gradient style depends on the
range of the Y axis and we change the range when zooming, the gradient color
positions need to be adjusted as the range changes. Do this by
defining proportional values for the gradient color positions:
\snippet 3d/widgetgraphgallery/highlightseries.cpp 2
The gradient modification is done in the \c handleGradientChange method, so
connect it to react to changes on the Y axis:
\snippet 3d/widgetgraphgallery/surfacegraphmodifier.cpp 16
When a change in the Y axis max value happens, calculate the new gradient
color positions:
\snippet 3d/widgetgraphgallery/highlightseries.cpp 3
\section1 Example Contents
*/