XCEngine/new_editor/app/Platform/Win32/EditorWindowTitleBarRendering.cpp

#include "Platform/Win32/EditorWindow.h"
#include "Platform/Win32/EditorWindowConstants.h"
#include "Platform/Win32/EditorWindowStyle.h"

#include <XCEditor/Foundation/UIEditorTheme.h>
#include <XCEditor/Panels/UIEditorPanelRegistry.h>
#include <XCEngine/UI/DrawData.h>
#include <XCEngine/UI/Layout/UITabStripLayout.h>

#include <algorithm>
#include <cmath>
#include <string_view>

#include <windowsx.h>

namespace XCEngine::UI::Editor::App {

using namespace EditorWindowSupport;
using ::XCEngine::UI::Layout::MeasureUITabStripHeaderWidth;
using ::XCEngine::UI::UIColor;
using ::XCEngine::UI::UIDrawList;
using ::XCEngine::UI::UIPoint;
using ::XCEngine::UI::UIRect;

namespace {

constexpr float kTitleBarLogoExtent = 16.0f;
constexpr float kTitleBarLogoInsetLeft = 8.0f;
constexpr float kTitleBarLogoTextGap = 8.0f;
std::string ResolveDetachedTitleTabText(const EditorWindow& window) {
    const auto& workspaceController = window.GetWorkspaceController();
    const std::string_view activePanelId = workspaceController.GetWorkspace().activePanelId;
    if (!activePanelId.empty()) {
        if (const UIEditorPanelDescriptor* descriptor =
                FindUIEditorPanelDescriptor(
                    workspaceController.GetPanelRegistry(),
                    activePanelId);
            descriptor != nullptr &&
            !descriptor->defaultTitle.empty()) {
            return descriptor->defaultTitle;
        }
    }

    return std::string("Panel");
}

float ResolveDetachedTabWidth(std::string_view text) {
    const Widgets::UIEditorTabStripMetrics& metrics = ResolveUIEditorTabStripMetrics();
    Widgets::UIEditorTabStripItem item = {};
    item.title = std::string(text);
    const float desiredLabelWidth =
        Widgets::ResolveUIEditorTabStripDesiredHeaderLabelWidth(item, metrics);
    return MeasureUITabStripHeaderWidth(desiredLabelWidth, metrics.layoutMetrics);
}

bool IsRootPanelVisible(
    const UIEditorWorkspaceController& controller,
    std::string_view panelId) {
    const UIEditorPanelSessionState* panelState =
        FindUIEditorPanelSessionState(controller.GetSession(), panelId);
    return panelState != nullptr && panelState->open && panelState->visible;
}

bool HasSingleVisibleRootTab(const UIEditorWorkspaceController& controller) {
    const UIEditorWorkspaceNode& root = controller.GetWorkspace().root;
    if (root.kind != UIEditorWorkspaceNodeKind::TabStack) {
        return false;
    }

    std::size_t visiblePanelCount = 0u;
    for (const UIEditorWorkspaceNode& child : root.children) {
        if (child.kind != UIEditorWorkspaceNodeKind::Panel ||
            !IsRootPanelVisible(controller, child.panel.panelId)) {
            continue;
        }

        ++visiblePanelCount;
        if (visiblePanelCount > 1u) {
            return false;
        }
    }

    return visiblePanelCount == 1u;
}

UIRect BuildDetachedTitleLogoRect(const Host::BorderlessWindowChromeLayout& layout) {
    const float availableLeft = layout.titleBarRect.x;
    const float availableRight = layout.minimizeButtonRect.x;
    const float centeredX = std::floor(
        layout.titleBarRect.x + layout.titleBarRect.width * 0.5f - kTitleBarLogoExtent * 0.5f);
    const float clampedX = (std::max)(
        availableLeft,
        (std::min)(centeredX, availableRight - kTitleBarLogoExtent));
    const float logoY =
        layout.titleBarRect.y +
        (std::max)(0.0f, (layout.titleBarRect.height - kTitleBarLogoExtent) * 0.5f);
    return UIRect(clampedX, logoY, kTitleBarLogoExtent, kTitleBarLogoExtent);
}

} // namespace

bool EditorWindow::ShouldUseDetachedTitleBarTabStrip() const {
    return !m_window.primary && HasSingleVisibleRootTab(m_composition.workspaceController);
}

Host::BorderlessWindowChromeHitTarget EditorWindow::HitTestBorderlessWindowChrome(
    LPARAM lParam) const {
    if (!IsBorderlessWindowEnabled() || m_window.hwnd == nullptr) {
        return Host::BorderlessWindowChromeHitTarget::None;
    }

    RECT clientRect = {};
    if (!GetClientRect(m_window.hwnd, &clientRect)) {
        return Host::BorderlessWindowChromeHitTarget::None;
    }

    const float clientWidthDips =
        PixelsToDips(static_cast<float>((std::max)(clientRect.right - clientRect.left, 1L)));
    const Host::BorderlessWindowChromeLayout layout =
        ResolveBorderlessWindowChromeLayout(clientWidthDips);
    return Host::HitTestBorderlessWindowChrome(
        layout,
        ConvertClientPixelsToDips(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)));
}

Host::BorderlessWindowChromeLayout EditorWindow::ResolveBorderlessWindowChromeLayout(
    float clientWidthDips) const {
    float leadingOccupiedRight = 0.0f;
    if (ShouldUseDetachedTitleBarTabStrip()) {
        leadingOccupiedRight = ResolveDetachedTabWidth(ResolveDetachedTitleTabText(*this));
    }

    return Host::BuildBorderlessWindowChromeLayout(
        UIRect(0.0f, 0.0f, clientWidthDips, kBorderlessTitleBarHeightDips),
        leadingOccupiedRight);
}

void EditorWindow::AppendBorderlessWindowChrome(
    UIDrawList& drawList,
    float clientWidthDips) const {
    if (!IsBorderlessWindowEnabled()) {
        return;
    }

    const Host::BorderlessWindowChromeLayout layout =
        ResolveBorderlessWindowChromeLayout(clientWidthDips);
    const bool useDetachedTitleBarTabStrip = ShouldUseDetachedTitleBarTabStrip();
    if (!useDetachedTitleBarTabStrip) {
        drawList.AddFilledRect(layout.titleBarRect, kShellSurfaceColor);
        drawList.AddLine(
            UIPoint(layout.titleBarRect.x, layout.titleBarRect.y + layout.titleBarRect.height),
            UIPoint(
                layout.titleBarRect.x + layout.titleBarRect.width,
                layout.titleBarRect.y + layout.titleBarRect.height),
            kShellBorderColor,
            1.0f);
    }

    if (!m_window.primary) {
        if (m_render.titleBarLogoIcon.IsValid()) {
            drawList.AddImage(
                BuildDetachedTitleLogoRect(layout),
                m_render.titleBarLogoIcon,
                UIColor(1.0f, 1.0f, 1.0f, 1.0f));
        }
    } else {
        const float iconX = layout.titleBarRect.x + kTitleBarLogoInsetLeft;
        const float iconY =
            layout.titleBarRect.y +
            (std::max)(0.0f, (layout.titleBarRect.height - kTitleBarLogoExtent) * 0.5f);
        if (m_render.titleBarLogoIcon.IsValid()) {
            drawList.AddImage(
                UIRect(iconX, iconY, kTitleBarLogoExtent, kTitleBarLogoExtent),
                m_render.titleBarLogoIcon,
                UIColor(1.0f, 1.0f, 1.0f, 1.0f));
        }

        const std::string& titleText =
            m_window.titleText.empty() ? std::string("XCEngine Editor") : m_window.titleText;
        drawList.AddText(
            UIPoint(
                iconX +
                    (m_render.titleBarLogoIcon.IsValid()
                         ? (kTitleBarLogoExtent + kTitleBarLogoTextGap)
                         : 4.0f),
                layout.titleBarRect.y +
                    (std::max)(
                        0.0f,
                        (layout.titleBarRect.height - kBorderlessTitleBarFontSize) * 0.5f - 1.0f)),
            titleText,
            kShellTextColor,
            kBorderlessTitleBarFontSize);
    }

    Host::AppendBorderlessWindowChrome(
        drawList,
        layout,
        m_chrome.chromeState,
        IsBorderlessWindowMaximized());
}

} // namespace XCEngine::UI::Editor::App