WIP [UI] Theme-aware onboarding banner with frosted light mode

Banner colours now derive from palette tokens at ~60fps (tick-driven,
equality-guarded setters) so scheme switches and live accent-picker
previews apply instantly:

- dark stages: byte-for-byte the original treatment (near-black stage
  from window hue, Highlight accent, white centre halo, vignette 0.62)
- light stages: pastel accent-hue wash instead of a neutral grey copy,
  brightness-lifted accent for additive glow legibility, deep-Highlight
  halo (uGlowColor) instead of white blowout, gentler vignette
  (uVignetteMin 0.88) so corners don't go muddy
- black logo silhouette variant selected on light stages
- theme picker preseeded with brand green (brand_colors.h single source)

WIP notes for next session:
- real-pixel wizard screenshot check still pending (headless capture
  exists: Xvfb :77 + isolated XDG_DATA_HOME; shader vs fallback pixel
  analysis not finished)
- user plans separately: promote Fusion to default theme, Default -> system

cockatrice/CMakeLists.txt

@@ -403,6 +403,7 @@ set(cockatrice_SOURCES
     src/interface/widgets/tabs/api/commander_spellbook/commander_bracket_widget.cpp
     src/interface/widgets/tabs/api/commander_spellbook/handle_commander_brackets.cpp
     src/interface/widgets/onboarding/banner_shader_config.h
+    src/interface/widgets/onboarding/brand_colors.h
     src/interface/widgets/onboarding/first_run_wizard.cpp
     src/interface/widgets/onboarding/first_run_wizard.h
     src/interface/widgets/onboarding/first_run_wizard_page.cpp

cockatrice/cockatrice.qrc

@@ -2,6 +2,7 @@
     <qresource prefix="/">
         <file>resources/cardback.svg</file>
         <file>resources/cockatrice.svg</file>
+        <file>resources/cockatrice-logo-black.svg</file>
         <file>resources/cockatrice-logo-white.svg</file>
         <file>resources/hand.svg</file>
         <file>resources/hr.jpg</file>

cockatrice/src/interface/widgets/onboarding/banner_shader_config.h

@@ -38,8 +38,11 @@ class BannerShaderConfig : public QObject
     Q_PROPERTY(QColor colorA READ colorA WRITE setColorA NOTIFY colorAChanged)
     Q_PROPERTY(QColor colorB READ colorB WRITE setColorB NOTIFY colorBChanged)
     Q_PROPERTY(QColor accent READ accent WRITE setAccent NOTIFY accentChanged)
+    Q_PROPERTY(QColor glowColor READ glowColor WRITE setGlowColor NOTIFY glowColorChanged)
+    Q_PROPERTY(qreal vignetteMin READ vignetteMin WRITE setVignetteMin NOTIFY vignetteMinChanged)
 
     Q_PROPERTY(bool logoVisible READ logoVisible WRITE setLogoVisible NOTIFY logoVisibleChanged)
+    Q_PROPERTY(bool logoDark READ logoDark WRITE setLogoDark NOTIFY logoDarkChanged)
     Q_PROPERTY(qreal logoGlow READ logoGlow WRITE setLogoGlow NOTIFY logoGlowChanged)
 
 public:
@@ -185,6 +188,30 @@ public:
         }
     }
 
+    QColor glowColor() const
+    {
+        return m_glowColor;
+    }
+    void setGlowColor(const QColor &c)
+    {
+        if (c != m_glowColor) {
+            m_glowColor = c;
+            emit glowColorChanged();
+        }
+    }
+
+    qreal vignetteMin() const
+    {
+        return m_vignetteMin;
+    }
+    void setVignetteMin(qreal v)
+    {
+        if (v != m_vignetteMin) {
+            m_vignetteMin = v;
+            emit vignetteMinChanged();
+        }
+    }
+
     bool logoVisible() const
     {
         return m_logoVisible;
@@ -197,6 +224,18 @@ public:
         }
     }
 
+    bool logoDark() const
+    {
+        return m_logoDark;
+    }
+    void setLogoDark(bool v)
+    {
+        if (v != m_logoDark) {
+            m_logoDark = v;
+            emit logoDarkChanged();
+        }
+    }
+
     qreal logoGlow() const
     {
         return m_logoGlow;
@@ -222,7 +261,10 @@ signals:
     void colorAChanged();
     void colorBChanged();
     void accentChanged();
+    void glowColorChanged();
+    void vignetteMinChanged();
     void logoVisibleChanged();
+    void logoDarkChanged();
     void logoGlowChanged();
 
 private:
@@ -239,11 +281,17 @@ private:
 
     bool m_frontIsA = true;
 
+    // Curated fallback seed values -- BannerHost overwrites these with
+    // palette-derived colours (see shader_banner_widget.cpp) before the first
+    // paint, so they only matter as a safe pre-first-apply default.
     QColor m_colorA{0x1A, 0x1A, 0x20};
     QColor m_colorB{0x0E, 0x0E, 0x12};
     QColor m_accent{0x8B, 0xDD, 0x6B};
+    QColor m_glowColor{Qt::white};
+    qreal m_vignetteMin = 0.62;
 
     bool m_logoVisible = false;
+    bool m_logoDark = false;
     qreal m_logoGlow = 1.0;
 };
 

cockatrice/src/interface/widgets/onboarding/brand_colors.h

@@ -0,0 +1,15 @@
+#ifndef BRAND_COLORS_H
+#define BRAND_COLORS_H
+
+#include <QColor>
+
+/** @brief Cockatrice brand green.
+ *
+ * Single source of truth for the onboarding brand accent: it backs the
+ * banner's shader-accent uniform as the curated fallback when the active
+ * palette resolves no usable Highlight, and it preseads the wizard's
+ * QuickSetupPanel so a freshly generated palette keeps the brand identity
+ * until the user picks their own look. */
+inline const QColor kCockatriceBrandGreen(0x8B, 0xDD, 0x6B);
+
+#endif // BRAND_COLORS_H

cockatrice/src/interface/widgets/onboarding/pages/theme_setup_page.cpp

@@ -5,6 +5,7 @@
 #include "../../interface/palette_editor/quick_setup_panel.h"
 #include "../../interface/theme_manager.h"
 #include "../../interface/widgets/general/background_sources.h"
+#include "../brand_colors.h"
 #include "libcockatrice/settings/appearance_settings.h"
 
 #include <QComboBox>
@@ -30,6 +31,12 @@ ThemeSetupPage::ThemeSetupPage(QWidget *parent) : FirstRunWizardPage(parent)
 
     quickSetupPanel = new QuickSetupPanel(this);
 
+    // Preseed with the brand green so a fresh install's generated palette --
+    // and therefore the banner accent, which follows QPalette::Highlight --
+    // keeps the Cockatrice identity until the user picks their own look.
+    // setAccentColor blocks signals, so this never triggers a generation.
+    quickSetupPanel->setAccentColor(kCockatriceBrandGreen);
+
     connect(themeCombo, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &ThemeSetupPage::onThemeChanged);
     connect(schemeCombo, QOverload<int>::of(&QComboBox::currentIndexChanged), this, &ThemeSetupPage::onSchemeChanged);
     connect(quickSetupPanel, &QuickSetupPanel::valueChanged, this, &ThemeSetupPage::onGenerateFromAccent);

cockatrice/src/interface/widgets/onboarding/qml/BrandBanner.qml

@@ -16,6 +16,8 @@ Item {
         property vector4d uColorA: Qt.vector4d(bannerConfig.colorA.r, bannerConfig.colorA.g, bannerConfig.colorA.b, 1.0)
         property vector4d uColorB: Qt.vector4d(bannerConfig.colorB.r, bannerConfig.colorB.g, bannerConfig.colorB.b, 1.0)
         property vector4d uAccent: Qt.vector4d(bannerConfig.accent.r, bannerConfig.accent.g, bannerConfig.accent.b, 1.0)
+        property vector4d uGlowColor: Qt.vector4d(bannerConfig.glowColor.r, bannerConfig.glowColor.g, bannerConfig.glowColor.b, 1.0)
+        property real uVignetteMin: bannerConfig.vignetteMin
         property real uLogoGlow: bannerConfig.logoGlow
         fragmentShader: "qrc:/onboarding/shaders/brand_banner.frag.qsb"
     }
@@ -33,16 +35,21 @@ Item {
         property vector4d uColorA: Qt.vector4d(bannerConfig.colorA.r, bannerConfig.colorA.g, bannerConfig.colorA.b, 1.0)
         property vector4d uColorB: Qt.vector4d(bannerConfig.colorB.r, bannerConfig.colorB.g, bannerConfig.colorB.b, 1.0)
         property vector4d uAccent: Qt.vector4d(bannerConfig.accent.r, bannerConfig.accent.g, bannerConfig.accent.b, 1.0)
+        property vector4d uGlowColor: Qt.vector4d(bannerConfig.glowColor.r, bannerConfig.glowColor.g, bannerConfig.glowColor.b, 1.0)
+        property real uVignetteMin: bannerConfig.vignetteMin
         property real uLogoGlow: bannerConfig.logoGlow
         fragmentShader: "qrc:/onboarding/shaders/brand_banner.frag.qsb"
     }
 
-    // The hero logo itself — breathes cleanly over a 0.5–1.0 opacity range
+    // The hero logo itself — breathes cleanly over a 0.5–1.0 opacity range.
+    // White silhouette on dark stages, black on light ones, so it stays
+    // readable in both modes.
     Image {
         id: logo
         anchors.centerIn: parent
         visible: bannerConfig.logoVisible
-        source: "qrc:/resources/cockatrice-logo-white.svg"
+        source: bannerConfig.logoDark ? "qrc:/resources/cockatrice-logo-black.svg"
+                                      : "qrc:/resources/cockatrice-logo-white.svg"
         width: root.height * 0.6
         height: width * (sourceSize.height > 0 ? sourceSize.height / Math.max(sourceSize.width, 1) : 1)
         fillMode: Image.PreserveAspectFit

cockatrice/src/interface/widgets/onboarding/shader_banner_widget.cpp

@@ -1,7 +1,10 @@
 #include "shader_banner_widget.h"
 
+#include "../../theme_manager.h"
 #include "banner_shader_config.h"
+#include "brand_colors.h"
 
+#include <QApplication>
 #include <QPainter>
 #include <QQmlContext>
 #include <QQmlEngine>
@@ -11,11 +14,68 @@
 
 namespace
 {
-// Near-black base palette -- the background is dark and quiet so the green
-// accent stands out.
-constexpr QRgb kColorA = 0x1A1A20;
-constexpr QRgb kColorB = 0x0E0E12;
-constexpr QRgb kAccent = 0x8BDD6B;
+// Curated near-black stage -- used only when the active palette resolves no
+// usable window colour. Matches the banner's original design (dark and quiet
+// so the accent stands out) and satisfies design-plans §2.1's "identity
+// survives a bare palette".
+constexpr QRgb kFallbackColorA = 0x1A1A20;
+constexpr QRgb kFallbackColorB = 0x0E0E12;
+
+struct SuggestedColors
+{
+    QColor colorA;
+    QColor colorB;
+    QColor accent;
+    QColor glowColor;
+    qreal vignetteMin = 0.62;
+    bool lightStage = false;
+};
+
+SuggestedColors suggestedBannerColors()
+{
+    const QPalette &pal = qApp->palette();
+    const QColor window = pal.color(QPalette::Active, QPalette::Window);
+    const QColor highlight = pal.color(QPalette::Active, QPalette::Highlight);
+    if (!window.isValid() || !highlight.isValid()) {
+        return {
+            QColor(kFallbackColorA), QColor(kFallbackColorB), kCockatriceBrandGreen, QColor(Qt::white), 0.62, false};
+    }
+
+    // Dress the stage for the scheme so the banner never fights the
+    // surrounding window in either mode. Dark palettes keep the original
+    // quiet near-black stage (lightness 29 → 16) with the theme's window
+    // hue; light palettes get a pastel "frosted accent" treatment built from
+    // the Highlight hue instead of a plain near-white copy: a gentle mint
+    // wash that clearly belongs to the theme.
+    const qreal luma = 0.299 * window.red() + 0.587 * window.green() + 0.114 * window.blue();
+    const bool lightStage = luma > 115.0;
+    if (lightStage) {
+        const int hue = highlight.hslHue();
+        // Achromatic accents (grey) get a neutral near-white stage instead.
+        const int stageSat = hue < 0 ? 0 : 35;
+        const int hueSafe = hue < 0 ? 0 : hue;
+        auto pastel = [hueSafe, stageSat](int lightness) { return QColor::fromHsl(hueSafe, stageSat, lightness); };
+        // Brightness-lifted accent for additive glows: Highlight on a light
+        // stage must be mid-bright to read (the shipped light Highlight is a
+        // deep green that washes out additively against white).
+        const int accentLightness = qBound(120, highlight.lightness() + 70, 165);
+        const int accentSaturation = hue < 0 ? 0 : qMax(highlight.hslSaturation(), 140);
+        const QColor liftedAccent = hue < 0 ? highlight : QColor::fromHsl(hueSafe, accentSaturation, accentLightness);
+        // The centre glow uses the deep Highlight itself -- a coloured halo
+        // behind the dark logo instead of a white blowout.
+        return {pastel(247), pastel(231), liftedAccent, highlight, 0.88, true};
+    }
+
+    // Dark stage: force the window hue down to the banner's curated darkness,
+    // scaling saturation away so chromatic palettes tint it without going
+    // muddy. White glow and the original strong vignette stay untouched.
+    auto stage = [&window](int lightness) {
+        const int hue = window.hslHue();
+        const int saturation = hue < 0 ? 0 : qBound(0, qRound(window.hslSaturation() * (lightness / 40.0)), 255);
+        return QColor::fromHsl(hue, saturation, lightness);
+    };
+    return {stage(29), stage(16), QColor(highlight), QColor(Qt::white), 0.62, false};
+}
 } // namespace
 
 class GradientFallbackWidget : public QWidget
@@ -23,15 +83,27 @@ class GradientFallbackWidget : public QWidget
 public:
     using QWidget::QWidget;
 
+    void setColors(const QColor &a, const QColor &b)
+    {
+        if (a != colorA || b != colorB) {
+            colorA = a;
+            colorB = b;
+        }
+    }
+
 protected:
     void paintEvent(QPaintEvent *) override
     {
         QPainter painter(this);
         QLinearGradient gradient(0, 0, width(), height());
-        gradient.setColorAt(0.0, QColor(kColorA));
-        gradient.setColorAt(1.0, QColor(kColorB));
+        gradient.setColorAt(0.0, colorA);
+        gradient.setColorAt(1.0, colorB);
         painter.fillRect(rect(), gradient);
     }
+
+private:
+    QColor colorA{QColor(kFallbackColorA)};
+    QColor colorB{QColor(kFallbackColorB)};
 };
 
 BannerHost::BannerHost(QWidget *parent) : QWidget(parent)
@@ -62,6 +134,9 @@ BannerHost::BannerHost(QWidget *parent) : QWidget(parent)
     connect(&clock, &QTimer::timeout, this, &BannerHost::tick);
     clock.setInterval(16); // ~60fps; the shader itself is cheap, this is just a wall clock
 
+    connect(themeManager, &ThemeManager::themeChanged, this, &BannerHost::applyThemeColors);
+    applyThemeColors();
+
     applyMotifPreset(currentMotif);
     updateAspect();
 }
@@ -123,9 +198,9 @@ void BannerHost::applyMotifPreset(Motif motif)
 
     const Preset p = presetFor(motif);
 
-    config->setColorA(QColor(kColorA));
-    config->setColorB(QColor(kColorB));
-    config->setAccent(QColor(kAccent));
+    config->setColorA(bannerColorA);
+    config->setColorB(bannerColorB);
+    config->setAccent(bannerAccent);
     config->setLogoVisible(motif == Motif::Welcome);
 
     if (isFirstApply) {
@@ -183,8 +258,33 @@ void BannerHost::hideEvent(QHideEvent *event)
     clock.stop();
 }
 
+void BannerHost::applyThemeColors()
+{
+    const SuggestedColors colors = suggestedBannerColors();
+    bannerColorA = colors.colorA;
+    bannerColorB = colors.colorB;
+    bannerAccent = colors.accent;
+
+    if (usingFallback) {
+        fallback->setColors(bannerColorA, bannerColorB);
+        fallback->update();
+    } else if (config) {
+        config->setColorA(bannerColorA);
+        config->setColorB(bannerColorB);
+        config->setAccent(bannerAccent);
+        config->setGlowColor(colors.glowColor);
+        config->setVignetteMin(colors.vignetteMin);
+        config->setLogoDark(colors.lightStage);
+    }
+}
+
 void BannerHost::tick()
 {
+    // Palette previews (e.g. accent drags in the wizard's QuickSetupPanel)
+    // apply qApp->palette() without firing themeChanged, so re-derive here;
+    // BannerShaderConfig's setters are equality-guarded, so this is a no-op
+    // unless the colours actually changed.
+    applyThemeColors();
     if (config) {
         qreal t = elapsed.elapsed() / 1000.0;
         config->setTime(t);

cockatrice/src/interface/widgets/onboarding/shader_banner_widget.h

@@ -1,6 +1,7 @@
 #ifndef SHADER_BANNER_WIDGET_H
 #define SHADER_BANNER_WIDGET_H
 
+#include <QColor>
 #include <QElapsedTimer>
 #include <QTimer>
 #include <QWidget>
@@ -53,6 +54,7 @@ protected:
 private slots:
     void tick();
     void onSceneGraphFailed();
+    void applyThemeColors();
 
 private:
     struct Preset
@@ -73,6 +75,12 @@ private:
     BannerShaderConfig *config = nullptr;
     GradientFallbackWidget *fallback = nullptr;
 
+    // Palette-derived banner colours -- the theme's window hue forced down to
+    // the banner's curated darkness, plus the theme's Highlight as accent.
+    QColor bannerColorA;
+    QColor bannerColorB;
+    QColor bannerAccent;
+
     QTimer clock;
     QElapsedTimer elapsed;
     Motif currentMotif = Motif::Welcome;

cockatrice/src/interface/widgets/onboarding/shaders/brand_banner.frag

@@ -28,6 +28,8 @@ layout(std140, binding = 0) uniform buf
     vec4 uColorA;
     vec4 uColorB;
     vec4 uAccent;
+    vec4 uGlowColor;
+    float uVignetteMin;
     float uLogoGlow;
 };
 
@@ -136,14 +138,17 @@ vec3 motifWelcome(vec2 uv, vec3 bg, float t)
     vec2 center = vec2(asp * 0.5, 0.5);
     float cDist = length(ac - center);
 
-    // Centre bloom at logo position; intensity scales with uLogoGlow
+    // Centre bloom at logo position; intensity scales with uLogoGlow. It
+    // uses the scheme-driven uGlowColor rather than plain white so light
+    // stages don't blow out (white halo on a near-white field) -- BannerHost
+    // feeds white on dark stages and the deep accent tone on light ones.
     float centreLight = bloom(cDist, 0.08 * asp, 0.40 * asp);
-    col += centreLight * 0.20 * uLogoGlow;
+    col += uGlowColor.rgb * centreLight * 0.20 * uLogoGlow;
 
     // Flow-noise shimmer gated by Gaussian mask at centre
     float shimmer = flowNoise(ac * 0.8 + vec2(55.0, 33.0), t * 0.05) * 0.5 + 0.5;
     float shimmerMask = exp(-(cDist * cDist) / (0.18 * asp * 0.18 * asp));
-    col += shimmer * shimmerMask * 0.04 * uLogoGlow;
+    col += uGlowColor.rgb * shimmer * shimmerMask * 0.04 * uLogoGlow;
 
     // 48 ember particles: hash-seeded position, speed, size, brightness.
     // Embers within a distance threshold of centre are deflected into an
@@ -456,6 +461,8 @@ void main()
     else if (uMode < 4.5) col = motifPreferences(uv, bg, t);
     else col = motifFinish(uv, bg, t);
 
-    col *= mix(0.62, 1.0, vignette(uv));
+    // Corner vignette; uVignetteMin is scheme-driven (0.62 on dark stages,
+    // gentler on light ones so near-white corners don't go muddy grey).
+    col *= mix(uVignetteMin, 1.0, vignette(uv));
     fragColor = vec4(col, 1.0) * qt_Opacity;
 }