创建圆角矩形纹理2D

我正在构建一个带有对话框的游戏，我希望能够以与最终幻想系列非常相似的风格以程序方式生成盒子的纹理（想像最终幻想VII http://i79.photobucket.com/albums/j148/Xngears/Final%20Fantasy/FFVII%20Retranslated/ff72009-03-1900-26-46-30.jpg）。这是我到目前为止所拥有的代码片段：

public class DialogBox
{
    public Rectangle BoxArea { get; set; }
    public List<Color> BoxColors { get; set; }
    public List<Color> BorderColors { get; set; }
    public int BorderThickness { get; set; }
    public int BorderRadius { get; set; }
    private Texture2D texture;

    public void CreateBackdrop(ref GraphicsDevice graphics)
    {
        texture = new Texture2D(graphics,
                                BoxArea.Width,
                                BoxArea.Height,
                                true,
                                SurfaceFormat.Color);
        Color[] color = new Color[texture.Width * texture.Height];

        for(int x = 0; x < texture.Width; x++)
        {
            for(int y = 0; y < texture.Height; y++)
            {
                switch(BoxColors.Count)
                {
                    case 4:
                        Color leftColor = Color.Lerp(BoxColor[0], BoxColor[1], (y / (texture.Height - 1)));
                        Color rightColor = Color.Lerp(BoxColor[2], BoxColor[3], (y / (texture.Height - 1)));
                        color[x + y * texture.Width] = Color.Lerp(leftColor,
                                                                  RightColor,
                                                                  (x / (texture.Width - 1)));
                        break;
                    case 2:
                        color[x + y * texture.Width] = Color.Lerp(BoxColors[0],
                                                                  BoxColors[1],
                                                                  (x / (texture.Width - 1)));
                        break;
                    default:
                        color[x + y * texture.Width];
                        break;
                 }
            }
        }
        texture.SetData<Color>(color);
    }
}

我正在寻找的是以下内容：

• 4路渐变色（已实现）
• 圆角矩形
• 渐变边框

任何帮助将不胜感激。

我通过以下方式找出了矩形这个问题 https://stackoverflow.com/questions/2792694/draw-rectangle-with-xna.

我弄清楚了我遇到的问题是什么；计算拐角圆弧。我发现人们可以使用距一点的距离来理解绘制边界的方法，而不是使用数学来计算圆内的点。下面我发布了生成圆角矩形的代码。

public Texture2D CreateRoundedRectangleTexture(GraphicsDevice graphics, int width, int height, int borderThickness, int borderRadius, int borderShadow, List<Color> backgroundColors, List<Color> borderColors, float initialShadowIntensity, float finalShadowIntensity)
{
    if (backgroundColors == null || backgroundColors.Count == 0) throw new ArgumentException("Must define at least one background color (up to four).");
    if (borderColors == null || borderColors.Count == 0) throw new ArgumentException("Must define at least one border color (up to three).");
    if (borderRadius < 1) throw new ArgumentException("Must define a border radius (rounds off edges).");
    if (borderThickness < 1) throw new ArgumentException("Must define border thikness.");
    if (borderThickness + borderRadius > height / 2 || borderThickness + borderRadius > width / 2) throw new ArgumentException("Border will be too thick and/or rounded to fit on the texture.");
    if (borderShadow > borderRadius) throw new ArgumentException("Border shadow must be lesser in magnitude than the border radius (suggeted: shadow <= 0.25 * radius).");

    Texture2D texture = new Texture2D(graphics, width, height, false, SurfaceFormat.Color);
    Color[] color = new Color[width * height];

    for (int x = 0; x < texture.Width; x++)
    {
        for (int y = 0; y < texture.Height; y++)
        {
            switch (backgroundColors.Count)
            {
                case 4:
                    Color leftColor0 = Color.Lerp(backgroundColors[0], backgroundColors[1], ((float)y / (width - 1)));
                    Color rightColor0 = Color.Lerp(backgroundColors[2], backgroundColors[3], ((float)y / (height - 1)));
                    color[x + width * y] = Color.Lerp(leftColor0, rightColor0, ((float)x / (width - 1)));
                    break;
                case 3:
                    Color leftColor1 = Color.Lerp(backgroundColors[0], backgroundColors[1], ((float)y / (width - 1)));
                    Color rightColor1 = Color.Lerp(backgroundColors[1], backgroundColors[2], ((float)y / (height - 1)));
                    color[x + width * y] = Color.Lerp(leftColor1, rightColor1, ((float)x / (width - 1)));
                    break;
                case 2:
                    color[x + width * y] = Color.Lerp(backgroundColors[0], backgroundColors[1], ((float)x / (width - 1)));
                    break;
                default:
                    color[x + width * y] = backgroundColors[0];
                    break;
            }

            color[x + width * y] = ColorBorder(x, y, width, height, borderThickness, borderRadius, borderShadow, color[x + width * y], borderColors, initialShadowIntensity, finalShadowIntensity);
        }
    }

    texture.SetData<Color>(color);
    return texture;
}

private Color ColorBorder(int x, int y, int width, int height, int borderThickness, int borderRadius, int borderShadow, Color initialColor, List<Color> borderColors, float initialShadowIntensity, float finalShadowIntensity)
{
    Rectangle internalRectangle = new Rectangle((borderThickness + borderRadius), (borderThickness + borderRadius), width - 2 * (borderThickness + borderRadius), height - 2 * (borderThickness + borderRadius));

    if (internalRectangle.Contains(x, y)) return initialColor;

    Vector2 origin = Vector2.Zero;
    Vector2 point = new Vector2(x, y);

    if (x < borderThickness + borderRadius)
    {
        if (y < borderRadius + borderThickness)
            origin = new Vector2(borderRadius + borderThickness, borderRadius + borderThickness);
        else if (y > height - (borderRadius + borderThickness))
            origin = new Vector2(borderRadius + borderThickness, height - (borderRadius + borderThickness));
        else
            origin = new Vector2(borderRadius + borderThickness, y);
    }
    else if (x > width - (borderRadius + borderThickness))
    {
        if (y < borderRadius + borderThickness)
            origin = new Vector2(width - (borderRadius + borderThickness), borderRadius + borderThickness);
        else if (y > height - (borderRadius + borderThickness))
            origin = new Vector2(width - (borderRadius + borderThickness), height - (borderRadius + borderThickness));
        else
            origin = new Vector2(width - (borderRadius + borderThickness), y);
    }
    else
    {
        if (y < borderRadius + borderThickness)
            origin = new Vector2(x, borderRadius + borderThickness);
        else if (y > height - (borderRadius + borderThickness))
            origin = new Vector2(x, height - (borderRadius + borderThickness));
    }

    if (!origin.Equals(Vector2.Zero))
    {
        float distance = Vector2.Distance(point, origin);

        if (distance > borderRadius + borderThickness + 1)
        {
            return Color.Transparent;
        }
        else if (distance > borderRadius + 1)
        {
            if (borderColors.Count > 2)
            {
                float modNum = distance - borderRadius;

                if (modNum < borderThickness / 2)
                {
                    return Color.Lerp(borderColors[2], borderColors[1], (float)((modNum) / (borderThickness / 2.0)));
                }
                else
                {
                    return Color.Lerp(borderColors[1], borderColors[0], (float)((modNum - (borderThickness / 2.0)) / (borderThickness / 2.0)));
                }
            }


            if (borderColors.Count > 0)
                return borderColors[0];
        }
        else if (distance > borderRadius - borderShadow + 1)
        {
            float mod = (distance - (borderRadius - borderShadow)) / borderShadow;
            float shadowDiff = initialShadowIntensity - finalShadowIntensity;
            return DarkenColor(initialColor, ((shadowDiff * mod) + finalShadowIntensity));
        }
    }

    return initialColor;
}

private Color DarkenColor(Color color, float shadowIntensity)
{
    return Color.Lerp(color, Color.Black, shadowIntensity);
}

With all of the code above, this is the result: