CODEWITHSUNDEEP
c#office-interop
Ruther Bergonia
Ruther Bergonia

Reputation: 137

How to determine the font color of the active document opened using word office interop in c#?

I have this code 

Word.Application WordApp = new Word.Application();
                WordApp.Visible = true;
                aDoc = WordApp.Documents.Open(fileName, ReadOnly: readOnly, Visible: isVisible);
                aDoc.Activate();

I wanted to determine the font color used in that opened document, Is there a way to do that? Thank you!

Upvotes: 0

Views: 2578

Answers (1)

Loathing
Loathing

Reputation: 5256

There might not be a single color that is used for all the text. However, you can access the color information, maintain a count of the occurrence of each color, and then pick the maximum.

The basic idea is that for each Range, get the Font, and for each Font, use its Color property. When accessing the ranges, it seems the choice is to iterate over the characters. Perhaps there is a better way, but I couldn't find it. To me, it seems somewhat inefficient to have to iterate over each character range to get its color versus the ability to access continuous blocks of text that have the same style or color formatting.

Also, the interop Font.Color property is not straightforward to translate to System.Drawing.Color. I found that .doc behaved as expected. However, for .docx the ColorTranslator.FromOle(font.Color) did not return the correct colors in some cases.

After some digging, I found an RgbColorConverter, which was copied from a link found in this thread: Office 2007 [and higher] interop: retrieve RGB-color

I thought it would be useful to reproduce here.

public static class WordColorTest {
    public static void GetColors() {

        Microsoft.Office.Interop.Word.Application app = new Microsoft.Office.Interop.Word.Application();
        Documents docs = app.Documents;
        Document doc = docs.Open("C:\\temp\\ColorTest3.docx", ReadOnly:true);
        StringBuilder sb = new StringBuilder();
        sb.AppendLine("<html><body>");
        sb.AppendLine("<table border=1 style='font-family:Arial;'>");
        sb.AppendLine("<tr><th>Text</th><th>RGB</th><th>Color</th></tr>");
        Dictionary<Color,int> counts = new Dictionary<Color,int>();

        foreach (Range rng in doc.StoryRanges) {
            foreach (Range rngChar in rng.Characters) { // by each character
                _Font f = rngChar.Font;
                int rgb = (int) f.Color;
                //System.Drawing.Color col = System.Drawing.ColorTranslator.FromOle(rgb); // do not use - not 1-to-1
                var col = RgbColorRetriever.GetRGBColor(f.Color, doc);
                //ColorFormat cf = f.TextColor; // error - exception on ".doc" files
                sb.AppendLine(String.Format("<tr><td>{0}</td><td>{1},{2},{3}</td><td bgcolor='{4}'></td></tr>", rngChar.Text, col.R, col.G, col.B, ToHex(col)));
                //sb.AppendLine(rngChar.Text + " " + col.R + "/" + col.G + "/" + col.B);

                if (f.Color != WdColor.wdColorAutomatic) {
                    if (counts.ContainsKey(col))
                        counts[col]++;
                    else
                        counts[col] = 1;
                }

                Marshal.ReleaseComObject(f);
                Marshal.ReleaseComObject(rngChar);
            }
            Marshal.ReleaseComObject(rng);
        }
        sb.AppendLine(String.Format("<tr><td colspan=3>&nbsp;</td></tr>"));

        foreach (Range rng in doc.StoryRanges) {
            foreach (Range rngWord in rng.Words) { // by each word
                _Font f = rngWord.Font;
                int rgb = (int) f.Color;
                //System.Drawing.Color col = System.Drawing.ColorTranslator.FromOle(rgb);  // do not use - not 1-to-1
                var col = RgbColorRetriever.GetRGBColor(f.Color, doc);
                sb.AppendLine(String.Format("<tr><td>{0}</td><td>{1},{2},{3}</td><td bgcolor='{4}'></td></tr>", rngWord.Text, col.R, col.G, col.B, ToHex(col)));
                //sb.AppendLine(rngWord.Text + " " + col.R + "/" + col.G + "/" + col.B);
                Marshal.ReleaseComObject(f);
                Marshal.ReleaseComObject(rngWord);
            }
            Marshal.ReleaseComObject(rng);
        }
        sb.AppendLine("</table>");
        sb.AppendLine("</body></html>");

        doc.Close(false);
        app.Quit(false);
        Marshal.ReleaseComObject(doc);
        Marshal.ReleaseComObject(docs);
        Marshal.ReleaseComObject(app);

        // if there is a tie, then there is the risk that the color will flip back and forth depending on how the dictionary is ordered
        Color max = counts.Count == 0 ? Color.Black : counts.Aggregate((i1,i2) => i1.Value > i2.Value ? i1 : i2).Key;
        String html = sb.ToString(); // testing only
    }

    private static String ToHex(System.Drawing.Color c) {
        return "#" + c.R.ToString("X2") + c.G.ToString("X2") + c.B.ToString("X2");
    }
}





/// <summary>
/// static class with rgb color retrieving logic: Microsoft.Office.Interop.Word.WdColor -> System.Drawing.Color
/// </summary>
public static class RgbColorRetriever {
    #region Constants

    // first byte of WdColor determines its format type
    private static readonly int
        RGB = 0x00,
        Automatic = 0xFF,
        System = 0x80,
        ThemeLow = 0xD0,
        ThemeHigh = 0xDF;

    //structure to store HSL (hue, saturation, lightness) color
    private struct HSL {
        public double H, S, L;
    }

    #endregion

    /// <summary>
    /// Get RGB-color from WdColor
    /// </summary>
    /// <param name="wdColor">source color</param>
    /// <param name="doc">document, where this color from (for appropriate color theme)</param>
    public static Color GetRGBColor(WdColor wdColor, Document doc) {
        // separate 1st byte (the most significant) and 3 others to different vars
        int color = ((int) wdColor) & ((int) 0xFFFFFF);
        int colorType = (int) (((uint) wdColor) >> 24);

        if (colorType == RGB) {
            // simple color in OLE format (it's just a BGR - blue, green, red) 
            // let's use standard color translator from system.drawing
            return ColorTranslator.FromOle(color);
        }
        else if (colorType == Automatic) {
            // standard contrast color. In my case I was needed color. But I don't know the proper way to understand which one (black or white) I need to choose.
            return Color.White;
        }
        else if (colorType == System) {
            // In ActiveX controls in documents, and in VBA (for UserForm controls, for example) special values for system colours 
            // (for some reason lost in the mists of time these are also called OLE Colors) ranging from 0x80000000 to 0x80000018. 
            // I used system dll function to retrieve system color and then used standard color translator
            int sysColor = GetSysColor(color);
            return ColorTranslator.FromOle(sysColor);
        }
        else if (colorType >= ThemeLow && colorType <= ThemeHigh) {
            // color based on doc's color theme
            return GetThemedColor(colorType, color, doc);
        }

        throw new Exception("Unknown color type");
    }

    private static Color GetThemedColor(int colorType, int color, Document doc) {
        // color based on theme is base color + tint or shade
        double tintAndShade = 0;
        // base color index is least siginficant 4 bits from colorType
        int colorThemeIndex = colorType & 0xF;

        // 2nd most significant byte is always 0
        // 3rd byte - shade, 4th - tint. One of them must be 0xFF and shouldn't be used
        // it means that always is used one of them and other is 0xFF
        int darkness = (color & 0x00FF00) >> 8;
        int lightness = color & 0x0000FF;

        if (darkness != 0xFF)
            tintAndShade = -1 + darkness / 255.0;
        else
            tintAndShade = 1.0 - lightness / 255.0;
        // so: 
        //      tintAndShade < 0 => shade base color by |tintAndShade| * 100%
        //      tintAndShade > 0 => tint base color |tintAndShade| * 100%

        return GetThemedColor(colorThemeIndex, tintAndShade, doc);
    }

    private static Color GetThemedColor(int colorThemeIndex, double tintAndShade, Document doc) {
        // translate from wdThemeColorIndex to MsoThemeColorSchemeIndex
        MsoThemeColorSchemeIndex colorSchemeIndex = ThemeIndexToSchemeIndex(colorThemeIndex);
        // get color scheme by this index and take its RGB property, but this RGB still OLE RGB - i.e. BGR -> need to convert it to real RGB, i.e. use ColorTranslator.FromOle() and ToArgb after
        OfficeTheme theme = doc.DocumentTheme;
        ThemeColorScheme scheme = theme.ThemeColorScheme;
        ThemeColor color = scheme.Colors(colorSchemeIndex);
        int colorSchemeRGB = ColorTranslator.FromOle(color.RGB).ToArgb();
        Marshal.ReleaseComObject(color);
        Marshal.ReleaseComObject(scheme);
        Marshal.ReleaseComObject(theme);

        // do RGB -> HSL translation to apply tint/shade
        HSL colorSchemeHSL = RGBtoHSL(colorSchemeRGB);

        // apply it
        if (tintAndShade > 0)
            colorSchemeHSL.L += (1 - colorSchemeHSL.L) * tintAndShade;
        else
            colorSchemeHSL.L *= 1 - Math.Abs(tintAndShade);

        // do backward HSL -> RGB translation
        int tintedAndShadedRGB = HSLtoRGB(colorSchemeHSL);

        return Color.FromArgb(tintedAndShadedRGB);
    }

    private static int HSLtoRGB(HSL HSL) {
        // took from https://stackoverflow.com/questions/2353211/hsl-to-rgb-color-conversion
        double red, green, blue;

        if (HSL.S == 0)
            red = green = blue = HSL.L;
        else {
            double q = HSL.L < 0.5 ? HSL.L * (1 + HSL.S) : HSL.L + HSL.S - HSL.L * HSL.S;
            double p = 2 * HSL.L - q;

            red = Hue2RGB(p, q, HSL.H + 1.0 / 3);
            green = Hue2RGB(p, q, HSL.H);
            blue = Hue2RGB(p, q, HSL.H - 1.0 / 3);
        }

        int r = (int) (red * 255), g = (int) (green * 255), b = (int) (blue * 255);
        return (r << 16) + (g << 8) + b;
    }

    private static double Hue2RGB(double p, double q, double t) {
        // took from https://stackoverflow.com/questions/2353211/hsl-to-rgb-color-conversion

        if (t < 0) t += 1;
        if (t > 1) t -= 1;
        if (t < 1.0 / 6) return p + (q - p) * 6 * t;
        if (t < 1.0 / 2) return q;
        if (t < 2.0 / 3) return p + (q - p) * (2.0 / 3 - t) * 6;
        return p;
    }

    private static HSL RGBtoHSL(int RGB) {
        // took from https://stackoverflow.com/questions/2353211/hsl-to-rgb-color-conversion
        double red, green, blue;
        double max, min, diff;

        red = ((RGB & 0xFF0000) >> 16) / 255.0;
        green = ((RGB & 0x00FF00) >> 8) / 255.0;
        blue = (RGB & 0x0000FF) / 255.0;

        max = Math.Max(red, Math.Max(green, blue));
        min = Math.Min(red, Math.Min(green, blue));
        diff = max - min;

        HSL res;
        res.L = res.H = res.S = (max + min) / 2;
        if (max == min)
            res.S = res.H = 0;
        else {
            res.S = res.L < 0.5 ? diff / (max + min) : diff / (2 - max - min);

            if (red == max)
                res.H = (green - blue) / diff - (blue > green ? 6 : 0);
            else if (green == max)
                res.H = (blue - red) / diff + 2;
            else if (blue == max)
                res.H = (red - green) / diff + 4;
            res.H /= 6;
        }

        return res;
    }

    private static MsoThemeColorSchemeIndex ThemeIndexToSchemeIndex(int colorThemeIndex) {
        // translation sheet from http://www.wordarticles.com/Articles/Colours/2007.php#UIConsiderations
        switch ((WdThemeColorIndex) colorThemeIndex) {
            case WdThemeColorIndex.wdThemeColorMainDark1:
                return MsoThemeColorSchemeIndex.msoThemeDark1;
            case WdThemeColorIndex.wdThemeColorMainLight1:
                return MsoThemeColorSchemeIndex.msoThemeLight1;
            case WdThemeColorIndex.wdThemeColorMainDark2:
                return MsoThemeColorSchemeIndex.msoThemeDark2;
            case WdThemeColorIndex.wdThemeColorMainLight2:
                return MsoThemeColorSchemeIndex.msoThemeLight2;
            case WdThemeColorIndex.wdThemeColorAccent1:
                return MsoThemeColorSchemeIndex.msoThemeAccent1;
            case WdThemeColorIndex.wdThemeColorAccent2:
                return MsoThemeColorSchemeIndex.msoThemeAccent2;
            case WdThemeColorIndex.wdThemeColorAccent3:
                return MsoThemeColorSchemeIndex.msoThemeAccent3;
            case WdThemeColorIndex.wdThemeColorAccent4:
                return MsoThemeColorSchemeIndex.msoThemeAccent4;
            case WdThemeColorIndex.wdThemeColorAccent5:
                return MsoThemeColorSchemeIndex.msoThemeAccent5;
            case WdThemeColorIndex.wdThemeColorAccent6:
                return MsoThemeColorSchemeIndex.msoThemeAccent6;
            case WdThemeColorIndex.wdThemeColorHyperlink:
                return MsoThemeColorSchemeIndex.msoThemeHyperlink;
            case WdThemeColorIndex.wdThemeColorHyperlinkFollowed:
                return MsoThemeColorSchemeIndex.msoThemeFollowedHyperlink;
            case WdThemeColorIndex.wdThemeColorBackground1:
                return MsoThemeColorSchemeIndex.msoThemeLight1;
            case WdThemeColorIndex.wdThemeColorText1:
                return MsoThemeColorSchemeIndex.msoThemeDark1;
            case WdThemeColorIndex.wdThemeColorBackground2:
                return MsoThemeColorSchemeIndex.msoThemeLight2;
            case WdThemeColorIndex.wdThemeColorText2:
                return MsoThemeColorSchemeIndex.msoThemeDark2;
            default:
                throw new Exception("Unknown WdThemeColorIndex: " + colorThemeIndex);
        }
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto)]
    public static extern int GetSysColor(int nIndex);
}

The following image illustrates the problems of directly passing the value of interop Font.Color to ColorTranslator.FromOle. Also, it shows that there is some kind of color blending that happens when requesting color information by each word Range.

Example of Wrong Colors

Upvotes: 5

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