Constant scaling factor for PageReader

[gowengit]

Constant scaling factor for PageReader

[Modest-as]

This is now supported in DocNet 2.0.0

[Modest-as]

Hey, you can also try reading and generating images one page at a time if you need more fine control how to scale the pages

[LokiMidgard]

That's what I'm currently doing. The problem is I can only specify the absolute result size for every page. Without knowing the original page size I don't know what the result size should be.

My workaround, using reflection to get the scaling and calculate the original size, then create a seccond page:

public static IPageReader GetPageReader(this DocLib library, string tmp, int pageIndex, double resolution)
{
    int widht, height;

    using (var docReader = library.GetDocReader(tmp, 1024, 1024))
    using (var page = docReader.GetPageReader(pageIndex))
    {
        var type = page.GetType();
        var member = type.GetField("_scaling", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
        var scaling = (double)member.GetValue(page);

        var originalHeight = page.GetPageHeight() / scaling;
        var originalWidth = page.GetPageWidth() / scaling;

        widht = (int)(originalWidth * resolution);
        height = (int)(originalHeight * resolution);
    }
    var doc2 = library.GetDocReader(tmp, widht, height);
    var pageReader = doc2.GetPageReader(pageIndex);
    return new PageReader(pageReader, doc2);
}

private class PageReader : IPageReader
{
    private readonly IPageReader pageReader;
    private readonly IDocReader doc2;

    public PageReader(IPageReader pageReader, IDocReader doc2)
    {
        this.pageReader = pageReader;
        this.doc2 = doc2;
    }

    public int PageIndex => this.pageReader.PageIndex;

    public void Dispose()
    {
        this.pageReader.Dispose();
        this.doc2.Dispose();
    }

    public IEnumerable<Character> GetCharacters() => this.pageReader.GetCharacters();

    public byte[] GetImage() => this.pageReader.GetImage();

    public int GetPageHeight() => this.pageReader.GetPageHeight();

    public int GetPageWidth() => this.pageReader.GetPageWidth();

    public string GetText() => this.pageReader.GetText();
}