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在 KDE Wayland 环境中使用 dbus 获取 UI 缩放比例 #6071

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在 KDE Wayland 环境中使用 dbus 获取 UI 缩放比例 #6071

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在 KDE Wayland 环境中使用 dbus 获取 UI 缩放比例
Glavo May 7, 2026
2c49ca1
Update HMCL/src/main/java/org/jackhuang/hmcl/EntryPoint.java
Glavo May 8, 2026
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65 changes: 57 additions & 8 deletions HMCL/src/main/java/org/jackhuang/hmcl/EntryPoint.java
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
import org.jackhuang.hmcl.util.io.FileUtils;
import org.jackhuang.hmcl.util.io.JarUtils;
import org.jackhuang.hmcl.util.platform.OperatingSystem;
import org.jackhuang.hmcl.util.platform.SystemUtils;

import javax.swing.JOptionPane;
import java.io.IOException;
Expand All @@ -32,6 +33,9 @@
import java.lang.invoke.MethodType;
import java.nio.file.Files;
import java.nio.file.Path;
import java.time.Duration;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.CancellationException;

import static org.jackhuang.hmcl.util.logging.Logger.LOG;
Expand Down Expand Up @@ -94,8 +98,49 @@ private static void setupJavaFXVMOptions() {
}
}

double scale = Double.NEGATIVE_INFINITY;

String uiScale = System.getProperty("hmcl.uiScale", System.getenv("HMCL_UI_SCALE"));
if (uiScale != null) {
if (uiScale == null) {
if (OperatingSystem.CURRENT_OS.isLinuxOrBSD()) {
String sessionType = System.getenv("XDG_SESSION_TYPE");
String currentDesktop = Objects.requireNonNullElse(System.getenv("XDG_CURRENT_DESKTOP"), "");

// On KDE Wayland, JavaFX cannot read the UI scale correctly.
if ("wayland".equals(sessionType) && currentDesktop.startsWith("kde")) {
Path dbusSend = SystemUtils.which("dbus-send");
if (dbusSend != null) {
try {
String[] result = SystemUtils.run(List.of(
FileUtils.getAbsolutePath(dbusSend),
"--session",
"--print-reply=literal",
"--reply-timeout=1000",
"--dest=org.freedesktop.portal.Desktop",
"/org/freedesktop/portal/desktop",
"org.freedesktop.portal.Settings.Read",
"string:org.kde.kdeglobals.KScreen",
"string:ScaleFactor"
), Duration.ofSeconds(2)).trim().split(" ");

if (result.length > 0) {
String value = result[result.length - 1];

try {
double scaleValue = Double.parseDouble(value.trim());
if (scaleValue > 1.0 && scaleValue <= 4) {
scale = scaleValue;
}
} catch (NumberFormatException ignored) {
}
}
} catch (Exception e) {
LOG.warning("Failed to get UI scale from D-Bus", e);
}
}
}
}
} else {
uiScale = uiScale.trim();

LOG.info("HMCL_UI_SCALE: " + uiScale);
Expand Down Expand Up @@ -123,20 +168,24 @@ private static void setupJavaFXVMOptions() {
}

if (scaleValue >= lowerBound && scaleValue <= upperBound) {
if (OperatingSystem.CURRENT_OS == OperatingSystem.WINDOWS) {
System.getProperties().putIfAbsent("glass.win.uiScale", uiScale);
} else if (OperatingSystem.CURRENT_OS == OperatingSystem.MACOS) {
LOG.warning("macOS does not support setting UI scale, so it will be ignored");
} else {
System.getProperties().putIfAbsent("glass.gtk.uiScale", uiScale);
}
scale = scaleValue;
} else {
LOG.warning("UI scale out of range: " + uiScale);
}
} catch (Throwable e) {
LOG.warning("Invalid UI scale: " + uiScale);
}
}

if (scale > 0) {
if (OperatingSystem.CURRENT_OS == OperatingSystem.WINDOWS) {
System.getProperties().putIfAbsent("glass.win.uiScale", uiScale);
} else if (OperatingSystem.CURRENT_OS == OperatingSystem.MACOS) {
LOG.warning("macOS does not support setting UI scale, so it will be ignored");
} else {
System.getProperties().putIfAbsent("glass.gtk.uiScale", uiScale);
}
}
Comment on lines +180 to +188
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@gemini-code-assist gemini-code-assist Bot May 7, 2026

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high

在通过 D-Bus 获取缩放比例的分支中（第 104-142 行），uiScale 变量保持为 null。由于 System.getProperties() 返回的是 Hashtable，调用 putIfAbsent 时传入 null 值会抛出 NullPointerException。此外，即使不抛出异常，也应该使用计算出的 scale 值，因为 JavaFX 的 uiScale 属性通常期望一个数值字符串，而不一定支持原始输入中的 % 或 dpi 后缀。

        if (scale > 0) {
            String scaleString = String.valueOf(scale);
            if (OperatingSystem.CURRENT_OS == OperatingSystem.WINDOWS) {
                System.getProperties().putIfAbsent("glass.win.uiScale", scaleString);
            } else if (OperatingSystem.CURRENT_OS == OperatingSystem.MACOS) {
                LOG.warning("macOS does not support setting UI scale, so it will be ignored");
            } else {
                System.getProperties().putIfAbsent("glass.gtk.uiScale", scaleString);
            }
        }

}

private static void createHMCLDirectories() {
Expand Down