feat(core+chart): ColorScale::stops() 暴露断点 + ColorMapService 连续插值色阶服务

- core::ColorScale 新增 stops() 方法，返回升序 (value, Rgba) 断点列表，供连续插值用。
- app::ColorMapService：从 ColorScale 构建，支持 normalized()/colorAtContinuous()/colorAtDiscrete()；
  连续模式在归一化断点位置间线性插值 RGB，与原版 Plotly colorscale 一致。
- cmake/qwt.cmake 补加 QWT_MOC_INCLUDE=1，修复 Qwt AUTOMOC self-include 宏保护缺失导致
  Q_OBJECT MOC 代码不编入 .obj 的链接错误（LNK2019 x61 系列）。
- 新增 TDD 测试 ColorMapService.*（4 个用例，全绿）。

cmake/qwt.cmake

@@ -24,6 +24,9 @@ set_target_properties(qwt PROPERTIES AUTOMOC ON)
 target_include_directories(qwt PUBLIC "${QWT_SRC_DIR}")
 target_link_libraries(qwt PUBLIC Qt6::Widgets Qt6::Concurrent Qt6::PrintSupport Qt6::Svg)
 target_compile_features(qwt PUBLIC cxx_std_17)
+# QWT_MOC_INCLUDE=1：启用 Qwt 源文件末尾 #if QWT_MOC_INCLUDE 保护的 #include "moc_xxx.cpp"。
+# Qwt 原生用 qmake（qwtbuild.pri 里设置），CMake 构建需显式定义，否则 MOC 元对象代码不被编译进 .obj。
+target_compile_definitions(qwt PRIVATE QWT_MOC_INCLUDE=1)
 if(MSVC)
   target_compile_options(qwt PRIVATE /bigobj /EHsc /wd4244 /wd4267 /wd4305 /wd4456)
 endif()

src/app/panels/chart/ColorMapService.cpp

@@ -0,0 +1,71 @@
+#include "panels/chart/ColorMapService.hpp"
+#include <algorithm>
+#include <cmath>
+
+namespace geopro::app {
+
+namespace {
+inline double clamp01(double v) {
+    return v < 0.0 ? 0.0 : (v > 1.0 ? 1.0 : v);
+}
+inline unsigned char lerpByte(unsigned char a, unsigned char b, double t) {
+    return static_cast<unsigned char>(a + (b - a) * t + 0.5);
+}
+}  // namespace
+
+ColorMapService::ColorMapService(const core::ColorScale& scale)
+    : scale_(scale) {
+    auto raw = scale.stops();
+    if (raw.empty()) {
+        minVal_ = 0.0;
+        maxVal_ = 1.0;
+        return;
+    }
+    minVal_ = raw.front().first;
+    maxVal_ = raw.back().first;
+    double range = maxVal_ - minVal_;
+    normStops_.reserve(raw.size());
+    for (const auto& [val, color] : raw) {
+        double pos = (range > 0.0) ? (val - minVal_) / range : 0.0;
+        normStops_.push_back({clamp01(pos), color});
+    }
+}
+
+double ColorMapService::normalized(double v) const {
+    double range = maxVal_ - minVal_;
+    if (range <= 0.0) return 0.0;
+    return clamp01((v - minVal_) / range);
+}
+
+core::Rgba ColorMapService::colorAtContinuous(double v) const {
+    if (normStops_.empty()) return core::Rgba{0, 0, 0, 255};
+    if (normStops_.size() == 1) return normStops_.front().color;
+
+    double t = normalized(v);
+
+    // 找到 t 落在哪两个 normStop 之间
+    if (t <= normStops_.front().pos) return normStops_.front().color;
+    if (t >= normStops_.back().pos)  return normStops_.back().color;
+
+    // 二分查找第一个 pos > t
+    auto it = std::upper_bound(normStops_.begin(), normStops_.end(), t,
+        [](double val, const NormStop& s) { return val < s.pos; });
+
+    const NormStop& hi = *it;
+    const NormStop& lo = *(it - 1);
+    double segLen = hi.pos - lo.pos;
+    double frac = (segLen > 0.0) ? (t - lo.pos) / segLen : 0.0;
+
+    return core::Rgba{
+        lerpByte(lo.color.r, hi.color.r, frac),
+        lerpByte(lo.color.g, hi.color.g, frac),
+        lerpByte(lo.color.b, hi.color.b, frac),
+        lerpByte(lo.color.a, hi.color.a, frac)
+    };
+}
+
+core::Rgba ColorMapService::colorAtDiscrete(double v) const {
+    return scale_.colorAt(v);
+}
+
+}  // namespace geopro::app

src/app/panels/chart/ColorMapService.hpp

@@ -0,0 +1,38 @@
+#pragma once
+#include "model/ColorScale.hpp"
+#include <vector>
+#include <utility>
+
+namespace geopro::app {
+
+// 连续/离散双模式色阶服务，供散点渲染（连续插值）和网格/图例（阶梯）使用。
+// 连续模式：按归一化位置在相邻断点之间线性插值 RGB，与原版 Plotly colorscale 一致。
+class ColorMapService {
+public:
+    explicit ColorMapService(const core::ColorScale& scale);
+
+    // 将数据值归一化到 [0,1]（min=首断点值, max=末断点值），超范围 clamp。
+    double normalized(double v) const;
+
+    // 连续插值取色（散点用）：按断点位置线性插值 RGB。
+    core::Rgba colorAtContinuous(double v) const;
+
+    // 离散阶梯取色（网格/图例用）：复用 ColorScale::colorAt。
+    core::Rgba colorAtDiscrete(double v) const;
+
+    // 返回原始 ColorScale 引用（色阶条图例用）。
+    const core::ColorScale& scale() const { return scale_; }
+
+private:
+    core::ColorScale scale_;
+    // 归一化位置与颜色预计算缓存（stops 已升序）。
+    struct NormStop {
+        double pos;  // normalized position in [0,1]
+        core::Rgba color;
+    };
+    std::vector<NormStop> normStops_;
+    double minVal_;
+    double maxVal_;
+};
+
+}  // namespace geopro::app

src/core/model/ColorScale.cpp

@@ -40,6 +40,13 @@ std::vector<double> ColorScale::stopValues() const {
     return v;
 }
 
+std::vector<std::pair<double, Rgba>> ColorScale::stops() const {
+    std::vector<std::pair<double, Rgba>> result;
+    result.reserve(stops_.size());
+    for (const auto& s : stops_) result.emplace_back(s.value, s.color);
+    return result;
+}
+
 Rgba ColorScale::colorAt(double value) const {
     if (std::isnan(value)) return nan_.value_or(Rgba{0, 0, 0, 0});
     if (stops_.empty()) return Rgba{0, 0, 0, 0};

src/core/model/ColorScale.hpp

@@ -1,5 +1,6 @@
 #pragma once
 #include <string>
+#include <utility>
 #include <vector>
 #include <optional>
 namespace geopro::core {
@@ -15,6 +16,8 @@ public:
     void addStop(double value, Rgba color);  // 内部保持按 value 升序
     Rgba colorAt(double value) const;        // 含 under/over/NaN 处理
     std::vector<double> stopValues() const;  // 升序分段值（供等值线用真实非均匀级）
+    // 返回升序断点 (value, color) 列表，供连续插值用。
+    std::vector<std::pair<double, Rgba>> stops() const;
     std::size_t stopCount() const { return stops_.size(); }
     void setUnder(Rgba c) { under_ = c; }
     void setOver(Rgba c)  { over_ = c; }

tests/CMakeLists.txt

@@ -88,6 +88,11 @@ endif()
 
 target_include_directories(geopro_tests PRIVATE ${CMAKE_SOURCE_DIR}/src/app)
 target_sources(geopro_tests PRIVATE app/test_chart_strategy_registry.cpp)
+# ColorMapService 测试（geopro_desktop 是可执行文件，直接把源加入测试目标）
+target_sources(geopro_tests PRIVATE
+    app/test_colormap_service.cpp
+    ${CMAKE_SOURCE_DIR}/src/app/panels/chart/ColorMapService.cpp
+)
 
 # controller 层：DatasetDetailController 编排集成测试（QSignalSpy 验证 chartReady/loadFailed）。
 find_package(Qt6 COMPONENTS Test REQUIRED)

tests/app/test_colormap_service.cpp

@@ -0,0 +1,46 @@
+#include <gtest/gtest.h>
+#include "panels/chart/ColorMapService.hpp"
+using namespace geopro;
+
+TEST(ColorMapService, ContinuousInterpolatesBetweenStops) {
+    core::ColorScale cs;
+    cs.addStop(0.0,   core::Rgba{0, 0, 0, 255});
+    cs.addStop(100.0, core::Rgba{255, 255, 255, 255});
+    app::ColorMapService svc(cs);
+    EXPECT_NEAR(svc.normalized(50.0), 0.5, 1e-9);
+    auto c = svc.colorAtContinuous(50.0);  // 黑白中点应约为灰
+    EXPECT_GT(c.r, 100); EXPECT_LT(c.r, 160);
+}
+
+TEST(ColorMapService, NormalizedClampsOutOfRange) {
+    core::ColorScale cs;
+    cs.addStop(0.0,   core::Rgba{0, 0, 0, 255});
+    cs.addStop(100.0, core::Rgba{255, 255, 255, 255});
+    app::ColorMapService svc(cs);
+    EXPECT_NEAR(svc.normalized(-10.0), 0.0, 1e-9);
+    EXPECT_NEAR(svc.normalized(110.0), 1.0, 1e-9);
+}
+
+TEST(ColorMapService, ColorAtContinuousAtExtremes) {
+    core::ColorScale cs;
+    cs.addStop(0.0,   core::Rgba{10, 20, 30, 255});
+    cs.addStop(100.0, core::Rgba{200, 210, 220, 255});
+    app::ColorMapService svc(cs);
+    auto cMin = svc.colorAtContinuous(0.0);
+    EXPECT_EQ(cMin.r, 10);
+    EXPECT_EQ(cMin.g, 20);
+    EXPECT_EQ(cMin.b, 30);
+    auto cMax = svc.colorAtContinuous(100.0);
+    EXPECT_EQ(cMax.r, 200);
+    EXPECT_EQ(cMax.g, 210);
+    EXPECT_EQ(cMax.b, 220);
+}
+
+TEST(ColorMapService, ScaleRefReturnsOriginal) {
+    core::ColorScale cs;
+    cs.addStop(0.0,   core::Rgba{0, 0, 0, 255});
+    cs.addStop(50.0,  core::Rgba{128, 0, 0, 255});
+    cs.addStop(100.0, core::Rgba{255, 0, 0, 255});
+    app::ColorMapService svc(cs);
+    EXPECT_EQ(svc.scale().stopCount(), 3u);
+}