Image generation: added tests

Source/QuestPDF.UnitTests/ImageGenerationTests.cs

@@ -0,0 +1,110 @@
+using System;
+using System.IO;
+using System.Linq;
+using FluentAssertions;
+using NUnit.Framework;
+using QuestPDF.Fluent;
+using QuestPDF.Helpers;
+using QuestPDF.Infrastructure;
+using SkiaSharp;
+
+namespace QuestPDF.UnitTests
+{
+    public class GenerateImageTests
+    {
+        [Test]
+        [TestCaseSource(nameof(GeneratedImageResolutionCorrespondsToTargetDpi_TestCases))]
+        public void GeneratedImageResolutionCorrespondsToTargetDpi(GeneratedImageResolutionCorrespondsToTargetDpi_TestCaseItem testCase)
+        {
+            // act
+            var images = Document
+                .Create(document => document.Page(page =>
+                {
+                    page.Size(testCase.PageSize);
+                    page.Content().Text("Test");
+                }))
+                .GenerateImages(new ImageGenerationSettings { RasterDpi = testCase.TargetDpi });
+            
+            // assert
+            images.Should().HaveCount(1);
+
+            var imageData = images.First();
+            imageData.Should().NotBeNull();
+            
+            using var image = SKImage.FromEncodedData(imageData);
+            image.Should().NotBeNull();
+            
+            image.Width.Should().Be(testCase.ExpectedImageSize.Width);
+            image.Height.Should().Be(testCase.ExpectedImageSize.Height);
+        }
+
+        public record GeneratedImageResolutionCorrespondsToTargetDpi_TestCaseItem(PageSize PageSize, int TargetDpi, ImageSize ExpectedImageSize);
+        
+        public static GeneratedImageResolutionCorrespondsToTargetDpi_TestCaseItem[] GeneratedImageResolutionCorrespondsToTargetDpi_TestCases =
+        {
+            new(new PageSize(150, 250), 72, new ImageSize(150, 250)),
+            new(new PageSize(200, 300), 144, new ImageSize(400, 600)),
+            new(new PageSize(250, 350), 360, new ImageSize(1250, 1750)),
+        };
+
+
+
+        [Test]
+        public void GeneratedImageSizeCorrespondsToImageQuality()
+        {
+            // arrange
+            var document = Document.Create(document => document.Page(page =>
+            {
+                page.Content().Image("Resources/photo.jpg");
+            }));
+            
+            // act
+            var imageSizeWithLowQuality = CheckImageSize(ImageCompressionQuality.Low);
+            var imageSizeWithMediumQuality = CheckImageSize(ImageCompressionQuality.Medium);
+            var imageSizeWithHighQuality = CheckImageSize(ImageCompressionQuality.High);
+            
+            // assert
+            imageSizeWithLowQuality.Should().BeLessThan(imageSizeWithMediumQuality);
+            imageSizeWithMediumQuality.Should().BeLessThan(imageSizeWithHighQuality);
+
+            int CheckImageSize(ImageCompressionQuality quality)
+            {
+                var images = document.GenerateImages(new ImageGenerationSettings() { ImageFormat = ImageFormat.Jpeg, ImageCompressionQuality = quality });
+                
+                images.Should().HaveCount(1);
+
+                var image = images.First();
+                image.Should().NotBeNull();
+
+                return image.Length;
+            }
+        }
+        
+        
+        [TestCase(ImageFormat.Png)]
+        [TestCase(ImageFormat.Jpeg)]
+        [TestCase(ImageFormat.Webp)]
+        public void ImageFormatIsRespected(ImageFormat imageFormat)
+        {
+            var images = Document
+                .Create(document =>
+                {
+                    document.Page(page =>
+                    {
+                        page.Content().Padding(25).AspectRatio(2).Background(Colors.Red.Medium);
+                    });
+                })
+                .GenerateImages(new ImageGenerationSettings() { ImageFormat = imageFormat });
+            
+            images.Should().HaveCount(1);
+
+            var imageData = images.First();
+            imageData.Should().NotBeNull();
+
+            using var imageStream = new MemoryStream(imageData);
+            using var imageCodec = SKCodec.Create(imageStream);
+
+            imageCodec.EncodedFormat.ToString().Should().Be(imageFormat.ToString());
+        }
+    }
+}

Source/QuestPDF.UnitTests/QuestPDF.UnitTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>netcoreapp3.1</TargetFramework>
+        <TargetFramework>net6.0</TargetFramework>
         <IsPackable>false</IsPackable>
         <LangVersion>9</LangVersion>
     </PropertyGroup>

Source/QuestPDF/Drawing/DocumentGenerator.cs

@@ -45,13 +45,14 @@ namespace QuestPDF.Drawing
                 throw new ArgumentException("The library requires a Stream object with the 'seek' capability available (the CanSeek flag). Please consider using the MemoryStream class.");
         }
         
-        internal static ICollection<byte[]> GenerateImages(IDocument document, ImageGenerationSettings settings)
+        internal static ICollection<byte[]> GenerateImages(IDocument document, ImageGenerationSettings imageGenerationSettings)
         {
             ValidateLicense();
             
             var documentSettings = document.GetSettings();
-            documentSettings.ImageRasterDpi = settings.RasterDpi;
-            var canvas = new ImageCanvas(settings);
+            documentSettings.ImageRasterDpi = imageGenerationSettings.RasterDpi;
+            
+            var canvas = new ImageCanvas(imageGenerationSettings);
             RenderDocument(canvas, document, documentSettings, useOriginalImages: true);
 
             return canvas.Images;