Panadapter background colors with NO image

[digver]

Request preparation

• I used an AI assistant to help structure this request
• I checked for existing issues covering the same feature

What would you like?

For some users the background images on the panadapter are distracting. This includes the default image.
Please:

1. Provide the option of choosing to NOT have a background image on the panadapter.
2. Allow the user to choose a background and graticule color

73, digger AB3XU

[aethersdr-agent]

Triage analysis

Thanks digger — good request, and most of the plumbing is already in place. Breaking it into the three asks:

1. "No background image" option

Partially supported in the engine, but no UI affordance reaches it:

• SpectrumWidget::setBackgroundImage() already handles an empty path → no image (src/gui/SpectrumWidget.cpp:4504-4520).
• The settings loader already treats the sentinel "none" as "do not load any image" (src/gui/SpectrumWidget.cpp:748-750).
• The overlay menu's Clear button is misnamed — it reverts to the bundled default :/bg-default.jpg rather than clearing (src/gui/SpectrumOverlayMenu.cpp:1331-1338, wired in src/gui/MainWindow.cpp:12235-12241, tooltip even reads "Revert to the default logo background").

So today there is no way to actually run with no image. The render path supports it; the UI just doesn't expose it.

2. User-chosen background color

Already implemented (#1741): the spectrum overlay menu has a Background: colour swatch that opens a QColorDialog and persists to BackgroundFillColor (src/gui/SpectrumOverlayMenu.cpp:1290-1340, handler at src/gui/MainWindow.cpp:12249-12257). With no image + this swatch, the user already gets a solid colored background — once part (1) is fixed.

3. User-chosen graticule color

Not currently configurable. drawGrid() hardcodes the theme token color.background.1 for both horizontal dB lines and vertical frequency lines (src/gui/SpectrumWidget.cpp:6319 and :6332). Needs a new setting + UI.

Proposed fix (handoff for maintainer)

Small, contained change spanning three files:

src/gui/SpectrumOverlayMenu.{h,cpp} — in the Background row (around :1290-1340):

• Rename existing Clear → Default (keep current behaviour: load :/bg-default.jpg).
• Add a new None button that emits a new signal backgroundImageNoneRequested().
• Add a new row beneath: Graticule: color swatch (mirror the existing m_bgFillColorBtn pattern), emitting graticuleColorChanged(QColor). Sync via a new arg added to syncExtraDisplaySettings().

src/gui/SpectrumWidget.{h,cpp}:

• Add void setGraticuleColor(const QColor&) / QColor graticuleColor() const accessors and QColor m_graticuleColor member (default: current color.background.1 value so existing users see no visual change).
• Persist via new settings key DisplayGraticuleColor; load alongside BackgroundFillColor at :752-756.
• Replace the two ThemeManager::instance().color("color.background.1") lookups in drawGrid() with m_graticuleColor.
• Call markOverlayDirty() on change.

src/gui/MainWindow.cpp — in the overlay-menu connect block (:12220-12257):

• Wire backgroundImageNoneRequested → sw->setBackgroundImage("") + persist "none" to settings.
• Wire graticuleColorChanged → sw->setGraticuleColor() + persist.
• Add both to the reset block (:12277-12329).

Classification

• enhancement, GUI, spectrum
• good first issue — well-scoped, follows the existing BackgroundFillColor pattern almost verbatim, no protocol or DSP work involved.

Marking maintainer-review for sign-off on the UI layout (specifically: keep one button labelled "Clear" with new behaviour vs. the rename-to-Default + add-None approach above). Once authorized I can implement.

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[jensenpat]

Added lean mode in display settings. Closed in #3286.