UI: Search combo property item with QVariant type

[norihiro]

Description

When finding current item for a combobox on properties view, use QVariant type to hold current values instead of converting all types into string.

Motivation and Context

A combobox created with OBS_COMBO_FORMAT_FLOAT cannot show the current item. When a modified callback for another item on the properties view returns true, the combobox is initialized again and the selection goes to the top item even though another item is selected.

When adding items into the combobox, userData is generated in the code below.

obs-studio/UI/properties-view.cpp

Lines 505 to 523 in e3f416f

	static void AddComboItem(QComboBox *combo, obs_property_t *prop,
	obs_combo_format format, size_t idx)
	{
	const char *name = obs_property_list_item_name(prop, idx);
	QVariant var;
	if (format == OBS_COMBO_FORMAT_INT) {
	long long val = obs_property_list_item_int(prop, idx);
	var = QVariant::fromValue<long long>(val);
	} else if (format == OBS_COMBO_FORMAT_FLOAT) {
	double val = obs_property_list_item_float(prop, idx);
	var = QVariant::fromValue<double>(val);
	} else if (format == OBS_COMBO_FORMAT_STRING) {
	var = QByteArray(obs_property_list_item_string(prop, idx));
	}
	combo->addItem(QT_UTF8(name), var);

OBS's type	userData generation function
OBS_COMBO_FORMAT_INT	QVariant::fromValue<long long>(long long)
OBS_COMBO_FORMAT_FLOAT	QVariant::fromValue<double>(double)
OBS_COMBO_FORMAT_STRING	QByteArray(const char *)

I'm implementing a plugin on norihiro/obs-color-monitor#54 and found this bug.

How Has This Been Tested?

OS: Fedora 35
Qt version: 5.15.2-31.fc35 and 6.2.3-2.fc35 (I checked with both versions.)

Checked these steps for xshm_input (using OBS_COMBO_FORMAT_INT) and slideshow (using OBS_COMBO_FORMAT_STRING).

• Create a source.
• Open it's properties view.
• Choose another item in combobox.
• Close the properties view and open it again.
• Check the combobox shows the same item.
  • Before this bugfix, the top item is always selected at this step for the combobox with OBS_COMBO_FORMAT_FLOAT.

Also checked another source under development using OBS_COMBO_FORMAT_FLOAT.

Need to check autoselect functionality but only available on two sources av_capture_input on macOS and dshow_input on Windows.

I've checked the signature and description of QComboBox::findData are same in between Qt5 and Qt6.
Qt5: https://doc.qt.io/qt-5/qcombobox.html#findData
Qt6: https://doc.qt.io/qt-6/qcombobox.html#findData

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
  • I didn't test autoselect functionality.
  • I didn't test on Windows though especially the behavior of QT_UTF8 is different on Windows.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[RytoEX]

I've checked the signature and description of QComboBox::findData are same in between Qt5 and Qt6.
Qt5: https://doc.qt.io/qt-5/qcombobox.html#findData
Qt6: https://doc.qt.io/qt-6/qcombobox.html#findData

See QTBUG-104990.
cc: @gxalpha

[norihiro]

However QTBUG-104990 claims the bug was introduced in Qt6, the issue was found in Qt5. Maybe OBS_COMBO_FORMAT_INT is broken by Qt6 but OBS_COMBO_FORMAT_FLOAT is not working in both Qt5 and Qt6.

[RytoEX]

However QTBUG-104990 claims the bug was introduced in Qt6, the issue was found in Qt5. Maybe OBS_COMBO_FORMAT_INT is broken by Qt6 but OBS_COMBO_FORMAT_FLOAT is not working in both Qt5 and Qt6.

I'm saying that the behavior of QComboBox::findData changes between Qt5 and Qt6, which is why I highlighted the text saying that the function is the same between Qt5 and Qt6.

[jpark37]

I know I just added two (optional) defects, but please merge this sooner than later. It's quite a nasty bug. The code looks good otherwise.

[jpark37]

Update the commit message. This is no longer just about OBS_COMBO_FORMAT_FLOAT.

[jpark37]

Looks good to me. Someone merge this ASAP as possible.

[gxalpha]

Seems to work fine, code changes make sense to me. In an ideal world, I'd love to hear back from QTBUG-104990 first, but even if it's a bug it would exist for some time so we'd need this anyways, so we should probably just merge it.