C#•2y ago

✅ Image from dataurl

I have dataurl with image and i need to get it to some reasonable image object in c#, so i can resize it and get bytes from the resized image. I was playing with skiasharp bitmap, but i couldn't figure it out.

20 Replies

Lexaro•2y ago

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace ImageConversionToHelpBinto86
{
    class Program
    {
        static void Main(string[] args)
        {
            string dataUrl = "";

            string base64 = dataUrl.Split(',')[1];

            byte[] imageBytes = Convert.FromBase64String(base64);

            using (MemoryStream ms = new MemoryStream(imageBytes))
            {
                Image image = Image.FromStream(ms);

                Bitmap resizedImage = new Bitmap(image, new Size(100, 100));

                byte[] resizedImageBytes;
                using (MemoryStream resizedMs = new MemoryStream())
                {
                    resizedImage.Save(resizedMs, ImageFormat.Jpeg);
                    resizedImageBytes = resizedMs.ToArray();
                }

            }
        }
    }
}

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace ImageConversionToHelpBinto86
{
    class Program
    {
        static void Main(string[] args)
        {
            string dataUrl = "";

            string base64 = dataUrl.Split(',')[1];

            byte[] imageBytes = Convert.FromBase64String(base64);

            using (MemoryStream ms = new MemoryStream(imageBytes))
            {
                Image image = Image.FromStream(ms);

                Bitmap resizedImage = new Bitmap(image, new Size(100, 100));

                byte[] resizedImageBytes;
                using (MemoryStream resizedMs = new MemoryStream())
                {
                    resizedImage.Save(resizedMs, ImageFormat.Jpeg);
                    resizedImageBytes = resizedMs.ToArray();
                }

            }
        }
    }
}

@Binto86 use my code to convert a data URL to an image in C#

Binto86OP•2y ago

thanks, unfortunately im not on windows, this is wasm, so i can't really use System.Drawing

Lexaro•2y ago

macOS? or Linux?

Binto86OP•2y ago

otherwise, im doing the same to extract the bytes from the url so... webassembly

Lexaro•2y ago

okay one second @Binto86 so i try to write a code for u with SkiaSharp

Binto86OP•2y ago

thank you i did try skiasharp but i couldn't get it to work with SKBitmap.Decode or anything im trying ImageSharp now

Lexaro•2y ago

using System;
using System.IO;
using SkiaSharp;

namespace ImageConversion
{
    public class Program
    {
        public static byte[] ConvertDataUrlToImageBytes(string dataUrl)
        {
            string base64 = dataUrl.Split(',')[1];

            byte[] imageBytes = Convert.FromBase64String(base64);

            using (MemoryStream ms = new MemoryStream(imageBytes))
            {
                using (SKManagedStream skStream = new SKManagedStream(ms))
                using (SKBitmap bitmap = SKBitmap.Decode(skStream))
                {
                    using (SKBitmap resizedBitmap = new SKBitmap(100, 100))
                    using (SKCanvas canvas = new SKCanvas(resizedBitmap))
                    {
                        canvas.DrawBitmap(bitmap, new SKRect(0, 0, 100, 100), BitmapStretch.Uniform);

                        using (MemoryStream resizedMs = new MemoryStream())
                        {
                            SKImage.FromBitmap(resizedBitmap).Save(resizedMs, SKEncodedImageFormat.Jpeg);
                            return resizedMs.ToArray();
                        }
                    }
                }
            }
        }
    }
}

using System;
using System.IO;
using SkiaSharp;

namespace ImageConversion
{
    public class Program
    {
        public static byte[] ConvertDataUrlToImageBytes(string dataUrl)
        {
            string base64 = dataUrl.Split(',')[1];

            byte[] imageBytes = Convert.FromBase64String(base64);

            using (MemoryStream ms = new MemoryStream(imageBytes))
            {
                using (SKManagedStream skStream = new SKManagedStream(ms))
                using (SKBitmap bitmap = SKBitmap.Decode(skStream))
                {
                    using (SKBitmap resizedBitmap = new SKBitmap(100, 100))
                    using (SKCanvas canvas = new SKCanvas(resizedBitmap))
                    {
                        canvas.DrawBitmap(bitmap, new SKRect(0, 0, 100, 100), BitmapStretch.Uniform);

                        using (MemoryStream resizedMs = new MemoryStream())
                        {
                            SKImage.FromBitmap(resizedBitmap).Save(resizedMs, SKEncodedImageFormat.Jpeg);
                            return resizedMs.ToArray();
                        }
                    }
                }
            }
        }
    }
}

@Binto86 try that @Binto86 working?

Binto86OP•2y ago

my SKImage doesn't have Save function im trying to solve that ok, did this instad

SKData d = SKImage.FromBitmap(bitmap).Encode(SKEncodedImageFormat.Png, 100);
d.SaveTo(resizedMs);

SKData d = SKImage.FromBitmap(bitmap).Encode(SKEncodedImageFormat.Png, 100);
d.SaveTo(resizedMs);

now im getting the bytes back i just can't tell if its actually resized or not anyways, thank you very much

Lexaro•2y ago

You can check the size of the resized image by comparing the width and height properties of the original SKBitmap and the resized SKBitmap.

Binto86OP•2y ago

i don't think it was but i changed the code a bit so hopefully

Lexaro•2y ago

okay text me if u need help again

Binto86OP•2y ago

yes it works tysm

Lexaro•2y ago

😊 No Problem

Binto86OP•2y ago

the skiasharp lib is acting really weird and unexpectedly

Lexaro•2y ago

What is happening? How long have you been programming with csharp? @Binto86

Binto86OP•2y ago

rn nothing as its solved 2 years

Lexaro•2y ago

okok

Binto86OP•2y ago

the api of the lib is just weird imo

Lexaro•2y ago

i correct the code wait

using System;
using System.IO;
using SkiaSharp;

namespace ImageConversion
{
    public class Program
    {
        public static byte[] ConvertDataUrlToImageBytes(string dataUrl)
        {
            string base64 = dataUrl.Split(',')[1];

            byte[] imageBytes = Convert.FromBase64String(base64);

            using (MemoryStream ms = new MemoryStream(imageBytes))
            {
                using (SKManagedStream skStream = new SKManagedStream(ms))
                using (SKBitmap bitmap = SKBitmap.Decode(skStream))
                {
                    using (SKBitmap resizedBitmap = new SKBitmap(100, 100))
                    using (SKCanvas canvas = new SKCanvas(resizedBitmap))
                    {
                        canvas.DrawBitmap(bitmap, new SKRect(0, 0, 100, 100), BitmapStretch.Uniform);

                        using (MemoryStream resizedMs = new MemoryStream())
                        {
                            SKData d = SKImage.FromBitmap(resizedBitmap).Encode(SKEncodedImageFormat.Png, 100);
                            d.SaveTo(resizedMs);
                            return resizedMs.ToArray();
                        }
                    }
                }
            }
        }
    }
}

using System;
using System.IO;
using SkiaSharp;

namespace ImageConversion
{
    public class Program
    {
        public static byte[] ConvertDataUrlToImageBytes(string dataUrl)
        {
            string base64 = dataUrl.Split(',')[1];

            byte[] imageBytes = Convert.FromBase64String(base64);

            using (MemoryStream ms = new MemoryStream(imageBytes))
            {
                using (SKManagedStream skStream = new SKManagedStream(ms))
                using (SKBitmap bitmap = SKBitmap.Decode(skStream))
                {
                    using (SKBitmap resizedBitmap = new SKBitmap(100, 100))
                    using (SKCanvas canvas = new SKCanvas(resizedBitmap))
                    {
                        canvas.DrawBitmap(bitmap, new SKRect(0, 0, 100, 100), BitmapStretch.Uniform);

                        using (MemoryStream resizedMs = new MemoryStream())
                        {
                            SKData d = SKImage.FromBitmap(resizedBitmap).Encode(SKEncodedImageFormat.Png, 100);
                            d.SaveTo(resizedMs);
                            return resizedMs.ToArray();
                        }
                    }
                }
            }
        }
    }
}

this should be a better version of the code and should work fine @Binto86

Binto86OP•2y ago

yes this is what i changed your original code to and works just fine

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✅ Image from dataurl