JUCE 8.0.13 released

emezeske · June 1, 2026, 2:07am

I believe the 8.0.13 release broke DPI scaling in some DAWs including Renoise (it gets applied twice, so JUCE’s UI is inflated extra large):

github.com/juce-framework/JUCE

VST3: Fix DPI scaling issues caused by JUCE 8.0.13 DPI changes (#1664)

master ← emezeske:dpi-fix-2026-05-31

opened 02:03AM - 01 Jun 26 UTC

emezeske

+13 -0

# Fix double-scaled plug-in editors on Windows in hosts that send a redundant co…ntent scale ## The problem On a high-DPI Windows display the plug-in UI has to be drawn bigger (e.g. 1.25x at 125%). There are **two independent ways** a plug-in can be told to do that: 1. **The OS way**: the window is marked per-monitor DPI-aware, and Windows scales it. 2. **The host way**: the host calls `IPlugViewContentScaleSupport::setContentScaleFactor(...)`. Some hosts do **both at once for the same factor**: the window is DPI-aware *and* the host also sends a content scale equal to the monitor's DPI. When that happens, if the desktop scaling is e.g. 1.25 JUCE applies the 1.25 twice and the editor renders at ~1.56x. I observed this in Renoise, where the plugin window is too large and scaled up too much. ## Why it works in most hosts but breaks in Renoise Most hosts pick **one** mechanism: per-monitor-aware hosts (Reaper, Cubase, etc.) rely on the OS and send no content scale (or 1.0). **Renoise** (and **Tracktion Waveform**) are DPI-aware *and* call `setContentScaleFactor` with a factor equal to the monitor DPI, so the same scale is counted twice. It is not a Renoise-specific bug; it is any host that supplies a content scale a DPI-aware window does not need. ## Why old JUCE worked and 8.0.13 broke it This regressed in **`fcf1971122` ("Plugin Client: Change scaling mechanism on Linux/Windows plugins")**, which changed *how* the host content scale is applied: - **Before 8.0.13:** the host content scale was applied as a **top-level `AffineTransform`** on the editor, independent of the window's OS/peer DPI scaling. The two lived in separate channels and did **not** stack, so a redundant host scale was harmless. - **In 8.0.13:** the host content scale is applied as the window's **platform scale** (`ComponentPeer::setCustomPlatformScaleFactor`), and `convertToHostBounds` now multiplies by `desktopScale * platformScale`. The host scale and the window's own DPI scaling now occupy the **same channel**, so a host scale that equals the DPI gets multiplied in on top of it, leading to double-scaling. ## The fix In `JuceVST3Editor::setContentScaleFactor`, ignore any content scale that is **at or below the window's own DPI scale** (`getScaleFactorForWindow`). The OS already applies that much to a DPI-aware window, so such a factor carries no new information; only a factor that **exceeds** the window's DPI represents extra scaling the host actually wants. This is correct in every case: - **DPI-aware window, redundant scale (Renoise / Waveform):** ignored: the OS's single DPI scaling stands. - **DPI-unaware window:** `getScaleFactorForWindow` returns 1.0, so a real host scale (> 1.0) is never mistaken for redundant and is still applied. - **Cubase 10 integer-scale workaround** (the existing block right below): its integer factor never equals the fractional window DPI, so that path is untouched. - **Genuine host zoom beyond the monitor DPI:** a factor greater than the window scale is still honored. It restores the pre-8.0.13 result (a single DPI scaling) without reverting the new mechanism, and is a no-op for any host that was not already sending a redundant content scale.

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JUCE 8.0.13 released

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JUCE 8.0.13 released

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