C++ Experiments

Concepts, solved problems and examples, available under MIT license

• Archive Helpers
  • arhelper_qt: Uses 7z binary to handle archive content
  • ar_history_search_qt: Store recent archives and filter the content
• Elementary Math
  • elementary_math_qml: Visualizations for math operations in elementary school
  • emvis1000_qml: Highlight solutions to plus / minus / multiply questions in the number range up to 1000
• File System Helpers
  • fs_filter_qt: Searchable tree view of a directory
  • fs_history_qt: Maintains a string list of existing files or directories in the order of last access
  • fs_history_search_qt: Store nine recent directories and filter the content
• Note Taking
  • Tiddlerstore: text storage based on tiddlywiki tiddler concept
  • Tiddlerstore_qt: Qt tools that utilize tiddlerstore
  • Tiddler_Inspector_qt: text based editor for tiddlers
• QTableView Demo: Code related to QTableView
• Qt Utilities
  • Combobox_Label_Elide_Left_Proxy_Style: If the text is too long for the label it will be elided left
  • tableview_adjust_row_visibility(): hide rows that became empty
  • tableview_resizeColumnsToContents_maxpercent(): resize column width up to a maximum if necessary
  • treeview_hide_expand(): hides rows in a tree view that don't match a given pattern

Build Requirements

• C++ 17 toolchain (e.g. gcc >= 7.3.0)
• CMake >= 3.11.0
• Qt >= 5.12.0
• nlohmann/json >= 3.4.0 for tiddlerstore, downloaded automatically if option EXPERIMENTS_USE_EXTERNAL_JSON is OFF (license: MIT)

Optional Tools

• GTest >= 1.10.0, downloaded automatically if option EXPERIMENTS_BUILD_TESTS is ON
• Doxygen documentation tool, enables apidoc build target
• GCov (part of gcc) / LCov for coverage report if option EXPERIMENTS_COVERAGE_REPORT is ON

Directory Structure

The top level structure follows the pitchfork layout.

docs/

Changelog.md

src/

arhelper_qt

Runtime dependencies:

• 7z executable in PATH

This library can create a model of the archive contents and extract a file or a tree to a given directory.

Enable build with cmake option EXPERIMENTS_ARHELPER_QT.

ar_history_search_qt

Application that combines arhelper_qt and fs_history_qt to provide filtering to archive contents like fs_history_search_qt. Double clicking a file or directory extracts it to a temporary folder and opens it in the operating system's default application.

Enabled if EXPERIMENTS_ARHELPER_QT, EXPERIMENTS_FS_HISTORY_QT and EXPERIMENTS_FS_FILTER_QT is on.

elementary_math_qml

The directory contains a QML file and its C++ bindings to highlight solutions to plus / minus / multiply questions in the number range up to 1000

Enable build with cmake option EXPERIMENTS_ELEMENTARY_MATH_QML.

emvis1000_qml

The application uses functions from elementary_math_qml to highlight solutions to plus / minus / multiply questions in the number range up to 1000.

Enabled if EXPERIMENTS_ELEMENTARY_MATH_QML is on.

fs_filter_qt

This widget shows a line edit above a tree view of an existing directory. The line edit filters all visible rows in the tree in a case insensitive way. You can expand every subdirectory automatically, so everything in the directory will be visible. This may take some time, so use only for not so huge directories, depending on your machine and patience. Directories that become empty during filtering and do not contain the filter text can optionally be hidden. If the filter line edit is empty, all directories are shown, even those that are empty without filtering.

Double clicking an element opens it in the associated application. Multiple elements can be selected, dragging is supported.

Enable build with cmake option EXPERIMENTS_FS_FILTER_QT.

fs_history_qt

The string list can either be used with files or with directories. Every element is watched whether it goes out of existence, which triggers removal from the list. The default list size is 9, so a hotkey can be applied to a menu entry. If the list is used on directories, you can provide a fallback directory which will be chosen if all other entries become invalid.

Some UI elements are provided that utilize the history list:

• combobox
• menu that adds a number as hotkey to each entry if the list size is 9 or less
• toolbutton to start a select file or directory dialog

Please try to only use the current_element_changed(const QString&) or elements_changed(const QStringList&) signals, because the widgets might fire twice when the list gets sorted because of a widget's trigger.

Enable build with cmake option EXPERIMENTS_FS_HISTORY_QT.

fs_history_search_qt

Application that combines fs_filter_qt and fs_history_qt. You have an initially empty combobox. To the right of it is a button to start a directory selection. Once a valid directory is selected, its content is shown below in a tree view that expands automatically, so please use only on not so huge directories. Between the combobox and the tree view is a line edit where you can filter the visible entries of the tree. If a directory gets emptied by filtering, it is hidden from view if its name does not contain the filter string.

Enabled if EXPERIMENTS_FS_FILTER_QT and EXPERIMENTS_FS_HISTORY_QT are on.

qtableview_demo

Application that demonstrates several features of a QTableView.

• horizontal scrolling for long cell: difference between "by item" and "by pixel"
• initial column sizes up to a maximum: resize column width up to a maximum if necessary
• hide rows in sparse tables: if a column gets hidden and only empty cells are left in a row, hide the row

Enable build with cmake option EXPERIMENTS_QTABLEVIEW_DEMO.

Qt_Utilities

Combobox_Label_Elide_Left_Proxy_Style: If the text is too long for the label it will be elided left

FlowLayout: BSD licensed flowlayout class from Qt examples, license is contained in the source files itself.

Qt_Utilities::tableview_adjust_row_visibility(): decide row visibility depending on decoration, background, disabled cells

Qt_Utilities::tableview_resizeColumnsToContents_maxpercent(): resize column width up to a maximum if necessary

Qt_Utilities::treeview_hide_expand(): hides rows in a tree view that don't match a given pattern and optionally fully expands the view

Enable build with cmake option EXPERIMENTS_ARHELPER_QT or EXPERIMENTS_FS_FILTER_QT or EXPERIMENTS_QTABLEVIEW_DEMO or EXPERIMENTS_TIDDLER_INSPECTOR_QT.

tiddlerstore

If you are looking for a great note taking application that also has the ability to store files and that runs everywhere please give tiddlywiki a try. Its concepts are used here to store text information

• title
• text with an adjustable content history
• tags (like a named bool: either present or not)
• fields (key / value pairs)
• lists (key / value list pairs)

together in one unit. Conversion to and from json is done using nlohmann/json.

Enable build with cmake option EXPERIMENTS_TIDDLER_INSPECTOR_QT

tiddlerstore_qt

Tiddler_Model: operates on a Tiddler and emits signals if a part of the Tiddler changes

Enable build with cmake option EXPERIMENTS_TIDDLER_INSPECTOR_QT

tiddler_inspector_qt

Text based editor for tiddlers

Enable build with cmake option EXPERIMENTS_TIDDLER_INSPECTOR_QT

tests/

Unit tests are placed separately from their sources, because measuring test coverage becomes incorrect if the test resides in the same directory as the source files. Test code coverage is of course 100%, so the overall coverage would look better than it is. Naming unit test files is done as described in the pitchfork paragraph Merged Test Placement.

The directories whose names match a directory name from src/ contain unit tests.

Included Resources

CMake file AddGoogleTest.cmake adapted from https://github.com/CLIUtils/cmake/blob/4e52e4d0bc2e9fd27171926d0b5d9f396dd8637c/AddGoogleTest.cmake is licensed under a BSD 3-Clause License (local copy): use URL instead of GIT

CMake file CodeCoverage.cmake adapted from https://github.com/bilke/cmake-modules/blob/7727aa773b8d72afe6801436af9e60cb1688351e/CodeCoverage.cmake is licensed under a BSD 3-Clause License included in the file itself: commented out COMMAND ${LCOV_PATH} --gcov-tool ${GCOV_PATH} --remove ${Coverage_NAME}.total ${COVERAGE_LCOV_EXCLUDES} ... and added COMMAND ${LCOV_PATH} --gcov-tool ${GCOV_PATH} --extract ${Coverage_NAME}.total ${COVERAGE_LCOV_INCLUDES} ...

Icon taken from openclipart is licensed under Creative Commons Zero 1.0 Public Domain License:

• emvis1000.svg (two.svg)