Feature: LinearGradient color decorator. (#592)

Based on the existing color decorators, create new ones to apply a gradient effect on the DOM. Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>
2025-12-16 01:48:56 +08:00 · 2023-03-22 09:59:02 -03:00
parent 2991b0389e
commit e83e90ced2
20 changed files with 671 additions and 106 deletions
--- a/src/ftxui/dom/linear_gradient_test.cpp
+++ b/src/ftxui/dom/linear_gradient_test.cpp
@@ -0,0 +1,90 @@
+#include <gtest/gtest.h>  // for Test, EXPECT_EQ, Message, TestPartResult, TestInfo (ptr only), TEST
+#include <ftxui/dom/linear_gradient.hpp>  // for LinearGradient::Stop, LinearGradient
+#include <string>                         // for allocator
+
+#include "ftxui/dom/elements.hpp"  // for operator|, text, bgcolor, color, Element
+#include "ftxui/dom/node.hpp"      // for Render
+#include "ftxui/screen/color.hpp"   // for Color, Color::Red, Color::RedLight
+#include "ftxui/screen/screen.hpp"  // for Screen, Pixel
+
+namespace ftxui {
+
+TEST(ColorTest, API_default) {
+  LinearGradient gradient;
+  EXPECT_EQ(gradient.angle, 0);
+  EXPECT_EQ(gradient.stops.size(), 0);
+}
+
+TEST(ColorTest, API_builder) {
+  auto gradient = LinearGradient()  //
+                      .Angle(45)
+                      .Stop(Color::Red)
+                      .Stop(Color::RedLight, 0.5)
+                      .Stop(Color::RedLight);
+  EXPECT_EQ(gradient.angle, 45);
+  EXPECT_EQ(gradient.stops.size(), 3);
+  EXPECT_EQ(gradient.stops[0].color, Color::Red);
+  EXPECT_EQ(gradient.stops[0].position, std::nullopt);
+  EXPECT_EQ(gradient.stops[1].color, Color::RedLight);
+  EXPECT_EQ(gradient.stops[1].position, 0.5);
+  EXPECT_EQ(gradient.stops[2].color, Color::RedLight);
+  EXPECT_EQ(gradient.stops[2].position, std::nullopt);
+}
+
+TEST(ColorTest, API_constructor_bicolor) {
+  auto gradient = LinearGradient(Color::Red, Color::RedLight);
+  EXPECT_EQ(gradient.angle, 0);
+  EXPECT_EQ(gradient.stops.size(), 2);
+  EXPECT_EQ(gradient.stops[0].color, Color::Red);
+  EXPECT_EQ(gradient.stops[0].position, std::nullopt);
+  EXPECT_EQ(gradient.stops[1].color, Color::RedLight);
+  EXPECT_EQ(gradient.stops[1].position, std::nullopt);
+}
+
+TEST(ColorTest, API_constructor_bicolor_angle) {
+  auto gradient = LinearGradient(45, Color::Red, Color::RedLight);
+  EXPECT_EQ(gradient.angle, 45);
+  EXPECT_EQ(gradient.stops.size(), 2);
+  EXPECT_EQ(gradient.stops[0].color, Color::Red);
+  EXPECT_EQ(gradient.stops[0].position, std::nullopt);
+  EXPECT_EQ(gradient.stops[1].color, Color::RedLight);
+  EXPECT_EQ(gradient.stops[1].position, std::nullopt);
+}
+
+TEST(ColorTest, GradientForeground) {
+  auto element =
+      text("text") | color(LinearGradient(Color::RedLight, Color::Red));
+  Screen screen(5, 1);
+  Render(screen, element);
+
+  Color gradient_begin = Color::Interpolate(0, Color::RedLight, Color::Red);
+  Color gradient_end = Color::Interpolate(1, Color::RedLight, Color::Red);
+
+  EXPECT_EQ(screen.PixelAt(0, 0).foreground_color, gradient_begin);
+  EXPECT_EQ(screen.PixelAt(0, 0).background_color, Color());
+
+  EXPECT_EQ(screen.PixelAt(4, 0).foreground_color, gradient_end);
+  EXPECT_EQ(screen.PixelAt(4, 0).background_color, Color());
+}
+
+TEST(ColorTest, GradientBackground) {
+  auto element =
+      text("text") | bgcolor(LinearGradient(Color::RedLight, Color::Red));
+  Screen screen(5, 1);
+  Render(screen, element);
+
+  Color gradient_begin = Color::Interpolate(0, Color::RedLight, Color::Red);
+  Color gradient_end = Color::Interpolate(1, Color::RedLight, Color::Red);
+
+  EXPECT_EQ(screen.PixelAt(0, 0).foreground_color, Color());
+  EXPECT_EQ(screen.PixelAt(0, 0).background_color, gradient_begin);
+
+  EXPECT_EQ(screen.PixelAt(4, 0).foreground_color, Color());
+  EXPECT_EQ(screen.PixelAt(4, 0).background_color, gradient_end);
+}
+
+}  // namespace ftxui
+
+// Copyright 2023 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.