Image rendering offset

[TheOriginalTom]

The implementation works well in a local dev environment, but I can't get a live site IIS to render the image properly. I must be doing something wrong. Can you help me? Here's a live site link to see the image rendering. com/account/register

[tossnet]

I can't trust a link pasted into an exit message. Share the code instead, and why not a screenshot as well..

[TheOriginalTom]

Sorry, I didn't think of that. Here's a screen shot and razor.

Register

Create a new account.

---

  The security letters do not match the picture. Try again.

        <div class="form-floating mb-3">
            <InputText @bind-Value="Input.Email" class="form-control" autocomplete="username" aria-required="true" placeholder="[email protected]" />
            <label for="email">Email</label>
            <ValidationMessage For="() => Input.Email" class="text-danger" />
        </div>
        <div class="form-floating mb-3">
            <InputText type="password" @bind-Value="Input.Password" class="form-control" autocomplete="new-password" aria-required="true" placeholder="password" />
            <label for="password">Password</label>
            <ValidationMessage For="() => Input.Password" class="text-danger" />
        </div>
        <div class="form-floating mb-3">
            <InputText type="password" @bind-Value="Input.ConfirmPassword" class="form-control" autocomplete="new-password" aria-required="true" placeholder="password" />
            <label for="confirm-password">Confirm Password</label>
            <ValidationMessage For="() => Input.ConfirmPassword" class="text-danger" />
        </div>

        <div class="form-floating mb-6">
            <div class="col-lg-12">
                <Captcha @bind-CaptchaWord="@Captcha" CharNumber="@CaptchaLength" Height="80" Width="260"/>
            </div>
        </div>
        <div class="form-floating mb-3">
            <InputText type="text" @bind-Value="Input.EnteredCaptchaText" class="form-control" id="idCaptcha" placeholder="Type the security letters above" required />
            <label for="idCaptcha">Type the security letters above</label>
            <p style="color: red;" hidden=@hideSecurityMatchResults>&nbsp;&nbsp;The security letters do not match the picture. Capitalization matters. Try again.</p>
        </div>
        <button type="submit" class="w-100 btn btn-lg btn-primary">Register</button>
        <p>&nbsp;</p>
    </EditForm>
</div>

[tossnet]

MeasureText de Skia seems depreciated. I'll make a small update with GetGlyphWidths. It's hard to know what went wrong

Blazor-Captcha/BlazorCaptcha/Captcha.cs

Line 122 in 24b5cf8

float width = font.MeasureText(l.Value, out rect);

[Govern24]

@tossnet the following refactored code works locally and on deployed version. ` private void Initialization()
{
if (string.IsNullOrEmpty(CaptchaWord)) return;

        RandomValue = new Random();

        _bgColor = new SKColor((byte)RandomValue.Next(70, 100),
                                (byte)RandomValue.Next(60, 80),
                                (byte)RandomValue.Next(50, 90)
                              );


        var fontFamilies = new string[] { "Open Sans", "Courier", "Arial", "Times New Roman" };

        Letters = new List<Letter>();

        if (!string.IsNullOrEmpty(CaptchaWord))
        {
            foreach (char c in CaptchaWord)
            {
                var letter = new Letter
                {
                    Value = c.ToString(),
                    Angle = RandomValue.Next(-15, 25),
                    ForeColor = new SKColor((byte)RandomValue.Next(100, 256),
                                            (byte)RandomValue.Next(110, 256),
                                            (byte)RandomValue.Next(90, 256)),
                    Family = fontFamilies[RandomValue.Next(0, fontFamilies.Length)],
                };

                Letters.Add(letter);
            }

            int effectiveCaptchaLength = Math.Max(CharNumber, CharNumber);
            int dynamicWidth = Width + (effectiveCaptchaLength - CharNumber) * 10;
            int dynamicHeight = Height;
            using SKBitmap bitmap = new(dynamicWidth, dynamicHeight);
            using SKCanvas canvas = new(bitmap);
            canvas.Clear(_bgColor);

            using (SKPaint paint = new())
            {
                float x = 10;

                foreach (Letter l in Letters)
                {
                    var typeface = SKTypeface.FromFamilyName(l.Family);
                    using (var font = new SKFont(typeface, RandomValue.Next(Height / 2, (Height / 2) + (Height / 4))))
                    {
                        font.Edging = SKFontEdging.Antialias;
                        paint.Color = l.ForeColor;
                        paint.IsAntialias = true;

                        float width = font.MeasureText(l.Value);

                        float textWidth = width;
                        var y = RandomValue.Next(26, 35);
                        canvas.DrawText(l.Value, x, y, SKTextAlign.Left, font, paint);
                        x += textWidth + 10;
                    }
                }

                canvas.DrawLine(0, RandomValue.Next(0, Height), Width, RandomValue.Next(0, Height), paint);
                canvas.DrawLine(0, RandomValue.Next(0, Height), Width, RandomValue.Next(0, Height), paint);
                paint.Style = SKPaintStyle.Stroke;
                canvas.DrawOval(RandomValue.Next(-Width, Width), RandomValue.Next(-Height, Height), Width, Height, paint);
            }

            using SKImage image = SKImage.FromBitmap(bitmap);
            using SKData data = image.Encode(SKEncodedImageFormat.Jpeg, 100);

            img = ConvStreamToBase64(data);

        }

    }

    private static string ConvStreamToBase64(SKData Data)
    {
        MemoryStream ms = new();
        Data.SaveTo(ms);

        byte[] byteArray = ms.ToArray();
        string b64String = Convert.ToBase64String(byteArray);

        return $"data:image/jpg;base64,{b64String}";
    }`                                                                                        

[tossnet]

@Govern24 Nice work though, it would still need a rotation

[Andrey-2021]

I have this problem to

[cyrileek]

Works locally but not on the server (Azure App). Same problem on both Firefox and Microsoft Edge. Nuget Package version 1.7.1.