From a8eea6e9c1f32d5562594656c68dc4b9f985b790 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Sat, 14 Nov 2020 09:46:34 +0100
Subject: Add x_offset to drawable::line to be able to have drawImage render
 images outside the parent area.

---
 test/paintertest.cc | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

(limited to 'test')

diff --git a/test/paintertest.cc b/test/paintertest.cc
index f471313..fb17a91 100644
--- a/test/paintertest.cc
+++ b/test/paintertest.cc
@@ -31,6 +31,37 @@
 #include "../plugingui/image.h"
 #include "../plugingui/font.h"
 
+class TestColour
+{
+public:
+	TestColour(std::uint8_t r, std::uint8_t g, std::uint8_t b, std::uint8_t a)
+		: colour(r, g, b, a) {}
+	TestColour(const GUI::Colour& colour)
+		: colour(colour) {}
+
+	bool operator!=(const TestColour& other) const
+	{
+		return
+			colour.red() != other.colour.red() ||
+			colour.green() != other.colour.green() ||
+			colour.blue() != other.colour.blue() ||
+			colour.alpha() != other.colour.alpha()
+			;
+	}
+
+	const GUI::Colour colour;
+};
+
+std::ostream& operator<<(std::ostream& stream, const TestColour& col)
+{
+	stream << "(" <<
+		static_cast<int>(col.colour.red()) << ", " <<
+		static_cast<int>(col.colour.green()) << ", " <<
+		static_cast<int>(col.colour.blue()) << ", " <<
+		static_cast<int>(col.colour.alpha()) << ")";
+	return stream;
+}
+
 class TestableCanvas
 	: public GUI::Canvas
 {
@@ -48,6 +79,37 @@ private:
 	GUI::PixelBufferAlpha pixbuf;
 };
 
+class TestImage
+	: public GUI::Image
+{
+public:
+	TestImage(std::uint8_t width, std::uint8_t height, bool alpha)
+		: GUI::Image(":resources/logo.png") // just load some default image
+	{
+		_width = width;
+		_height = height;
+		has_alpha = alpha;
+
+		image_data.resize(_width * _height);
+		image_data_raw.resize(_width * _height);
+
+		// Store x and y coordinates as red and green colour components
+		for(std::uint8_t x = 0; x < _width; ++x)
+		{
+			for(std::uint8_t y = 0; y < _height; ++y)
+			{
+				image_data[x + _width * y] = GUI::Colour(x, y, 0, alpha ? 128 : 255);
+				image_data_raw[4 * (x + _width * y) + 0] = x;
+				image_data_raw[4 * (x + _width * y) + 1] = y;
+				image_data_raw[4 * (x + _width * y) + 2] = 0;
+				image_data_raw[4 * (x + _width * y) + 3] = alpha ? 128 : 255;
+			}
+		}
+
+		valid = true;
+	}
+};
+
 class PainterTest
 	: public uUnit
 {
@@ -56,6 +118,7 @@ public:
 	{
 		uUNIT_TEST(PainterTest::testDrawImage);
 		uUNIT_TEST(PainterTest::testDrawText);
+		uUNIT_TEST(PainterTest::testClipping);
 	}
 
 	void testDrawImage()
@@ -153,6 +216,35 @@ public:
 			                 font, someText);
 		}
 	}
+
+	// Test rendering images outside the container is being clipped correctly.
+	void testClipping()
+	{
+		TestableCanvas canvas(100, 100);
+		GUI::Painter painter(canvas);
+
+		{ // Without alpha
+			TestImage image(16, 16, false);
+			painter.clear();
+			painter.drawImage(-10, -10, image);
+			auto& pixbuf = canvas.getPixelBuffer();
+
+			// Top left corner pixel should have the RGBA value (10, 10, 0, 255)
+			uUNIT_ASSERT_EQUAL(TestColour(10, 10, 0, 255),
+			                   TestColour(pixbuf.pixel(0, 0)));
+		}
+
+		{ // With alpha (different pipeline)
+			TestImage image(16, 16, true);
+			painter.clear();
+			painter.drawImage(-10, -10, image);
+			auto& pixbuf = canvas.getPixelBuffer();
+
+			// Top left corner pixel should have the RGBA value (10, 10, 0, 128)
+			uUNIT_ASSERT_EQUAL(TestColour(10, 10, 0, 128),
+			                   TestColour(pixbuf.pixel(0, 0)));
+		}
+	}
 };
 
 // Registers the fixture into the 'registry'
-- 
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