New! TextProOnACylinder.cs

[aidanwolf]

If you're looking to curve the text like it would appear around cylinder, here is a quick code edit to the original TextProOnACircle to make that happen

using UnityEngine;
using System.Collections;
using TMPro;

namespace ntw.CurvedTextMeshPro
{
    /// <summary>
    /// Class for drawing a Text Pro text following a circle arc
    /// </summary>
    [ExecuteInEditMode]
    public class TextProOnACylinder : TextProOnACurve
    {
        /// <summary>
        /// The radius of the text circle arc
        /// </summary>
        [SerializeField]
        [Tooltip("The radius of the text circle arc")]
        private float m_radius = 10.0f;

        /// <summary>
        /// How much degrees the text arc should span
        /// </summary>
        [SerializeField]
        [Tooltip("How much degrees the text arc should span")]
        private float m_arcDegrees = 90.0f;

        /// <summary>
        /// The angular offset at which the arc should be centered, in degrees.
        /// -90 degrees means that the text is centered on the heighest point
        /// </summary>
        [SerializeField]
        [Tooltip("The angular offset at which the arc should be centered, in degrees")]
        private float m_angularOffset = -90;

        /// <summary>
        /// How many maximum degrees per letters should be. For instance, if you specify
        /// 10 degrees, the distance between the letters will never be superior to 10 degrees.
        /// It is useful to create text that gracefully expands until it reaches the full arc,
        /// without making the letters to sparse when the string is short
        /// </summary>
        [SerializeField]
        [Tooltip("The maximum angular distance between letters, in degrees")]
        private int m_maxDegreesPerLetter = 360;

        /// <summary>
        /// Previous value of <see cref="m_radius"/>
        /// </summary>
        private float m_oldRadius = float.MaxValue;

        /// <summary>
        /// Previous value of <see cref="m_arcDegrees"/>
        /// </summary>
        private float m_oldArcDegrees = float.MaxValue;

        /// <summary>
        /// Previous value of <see cref="m_angularOffset"/>
        /// </summary>
        private float m_oldAngularOffset = float.MaxValue;

        /// <summary>
        /// Previous value of <see cref="m_maxDegreesPerLetter"/>
        /// </summary>
        private float m_oldMaxDegreesPerLetter = float.MaxValue;

        /// <summary>
        /// Method executed at every frame that checks if some parameters have been changed
        /// </summary>
        /// <returns></returns>
        protected override bool ParametersHaveChanged()
        {
            //check if paramters have changed and update the old values for next frame iteration
            bool retVal = m_radius != m_oldRadius || m_arcDegrees != m_oldArcDegrees || m_angularOffset != m_oldAngularOffset || m_oldMaxDegreesPerLetter != m_maxDegreesPerLetter;

            m_oldRadius = m_radius;
            m_oldArcDegrees = m_arcDegrees;
            m_oldAngularOffset = m_angularOffset;
            m_oldMaxDegreesPerLetter = m_maxDegreesPerLetter;

            return retVal;
        }

        /// <summary>
        /// Computes the transformation matrix that maps the offsets of the vertices of each single character from
        /// the character's center to the final destinations of the vertices so that the text follows a curve
        /// </summary>
        /// <param name="charMidBaselinePosfloat">Position of the central point of the character</param>
        /// <param name="zeroToOnePos">Horizontal position of the character relative to the bounds of the box, in a range [0, 1]</param>
        /// <param name="textInfo">Information on the text that we are showing</param>
        /// <param name="charIdx">Index of the character we have to compute the transformation for</param>
        /// <returns>Transformation matrix to be applied to all vertices of the text</returns>
        protected override Matrix4x4 ComputeTransformationMatrix(Vector3 charMidBaselinePos, float zeroToOnePos, TMP_TextInfo textInfo, int charIdx)      
        {
            //calculate the actual degrees of the arc considering the maximum distance between letters
            float actualArcDegrees = Mathf.Min(m_arcDegrees, textInfo.characterCount / textInfo.lineCount * m_maxDegreesPerLetter);

            //compute the angle at which to show this character.
            //We want the string to be centered at the top point of the circle, so we first convert the position from a range [0, 1]
            //to a [-0.5, 0.5] one and then add m_angularOffset degrees, to make it centered on the desired point
            float angle = ((zeroToOnePos - 0.5f) * actualArcDegrees + m_angularOffset) * Mathf.Deg2Rad; //we need radians for sin and cos

            //compute the coordinates of the new position of the central point of the character. Use sin and cos since we are on a circle.
            //Notice that we have to do some extra calculations because we have to take in count that text may be on multiple lines
            float x0 = Mathf.Cos(angle);            
            float y0 = Mathf.Sin(angle);
            float radiusForThisLine = m_radius - textInfo.lineInfo[0].lineExtents.max.y * textInfo.characterInfo[charIdx].lineNumber;
            Vector2 newMideBaselinePos = new Vector2(x0 * radiusForThisLine, -y0 * radiusForThisLine); //actual new position of the character

            //compute the trasformation matrix: move the points to the just found position, then rotate the character to fit the angle of the curve 
            //(-90 is because the text is already vertical, it is as if it were already rotated 90 degrees)
            return Matrix4x4.TRS(new Vector3(-newMideBaselinePos.x, 0, newMideBaselinePos.y), Quaternion.AngleAxis(-Mathf.Atan2(y0, x0) * Mathf.Rad2Deg + 90, Vector3.up), Vector3.one);
        }
    }
}