CODEWITHSUNDEEP
c#imagebitmapbmppixelformat
chuel
chuel

Reputation: 58

Create a bitmap in c# with specific pixelformat from an image without loading the image

sorry if this question is silly, i'm just starting with C#

I have an image in disk which I know the path. The image is 20000x10000 aprox in size and around 400MB in size (i know this looking at the image)

I need to load it in the code and resize it since the progam dies if I try to put in a picture box 400m of image, but if I do

        Bitmap b0 = new Bitmap(pathImage);
        int newWidth = (int)(b0.Width * escala);
        int newHeight = (int)(b0.Height * escala);

        // Convert other formats (including CMYK) to RGB.
        Bitmap newImage = new Bitmap(newWidth, newHeight, System.Drawing.Imaging.PixelFormat.Format24bppRgb);

        // Draws the image in the specified size with quality mode set to HighQuality
        using (Graphics graphics = Graphics.FromImage(newImage))
        {
            graphics.CompositingQuality = CompositingQuality.HighQuality;
            graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            graphics.SmoothingMode = SmoothingMode.HighQuality;
            graphics.DrawImage(b0, 0, 0, newWidth, newHeight);
        }

But when I do Bitmap b0 = new Bitmap(pathImage); it just dies since 20000x10000x32 it's too much for my poor memory.

The problem is that if not specified, c# just uses as pixel format Format32bppArgb but I want Format1bppIndexed, and the only way i've found to change the format is with the constructor

Bitmap( int width, int height, int stride, PixelFormat format, IntPtr scan0 )

But for this constructor I need to know the size of the image, which in the code I don't know because it dies before the code can get it and know the size...

I'm lost. Any ideas?

EDIT: Doing this int width;

        int height;
        Image tif;
        using (FileStream file = new FileStream(rutaImagenEntrada, FileMode.Open, FileAccess.ReadWrite))
        {
            using ( tif = Image.FromStream(stream: file,
                                                useEmbeddedColorManagement: false,
                                                validateImageData: false))
            {
                width = (int)tif.PhysicalDimension.Width;
                height = (int)tif.PhysicalDimension.Height;
                
            }
            file.Close();
        }

I get the size of the image I cannot load, and can create a bitmap with the pixelformat and size that i wanted, BUT everyway I try to upload it doesn't work, it still crashes on me. I've tried using graphics .draw(tiff...) and tiff.getThumbnail(new size...) and it just dies on me. It targets x86 and the .Net 3.5 since those are the requirements of the client...

Any ideas?

Upvotes: 3

Views: 4043

Answers (1)

JaimeBarrachina
JaimeBarrachina

Reputation: 428

If FileStream works to open the file, you might want to give some of the other constructors of Bitmap a try, in particular Bitmap(Stream).

If that doesn't help, you might try loading the raw bmp data, creating a Bitmap with the format you want and copying the data into the Bitmap manually (I'm not familiar with C# Bitmaps, but there should be some way of accessing the data).

Hope this helps.

Upvotes: 1

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