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@PureWeen
Last active December 20, 2018 23:21
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Border Drawable
using System;
using System.Linq;
using Android.Graphics;
using Android.Graphics.Drawables;
using AColor = Android.Graphics.Color;
namespace Xamarin.Forms.Platform.Android
{
internal class BorderDrawable : Drawable
{
public const int DefaultCornerRadius = 2; // Default value for Android material button.
readonly Func<double, float> _convertToPixels;
bool _isDisposed;
Bitmap _normalBitmap;
bool _pressed;
Bitmap _pressedBitmap;
float _paddingLeft;
float _paddingTop;
Color _defaultColor;
readonly bool _drawOutlineWithBackground;
AColor _shadowColor;
float _shadowDx;
float _shadowDy;
float _shadowRadius;
float PaddingLeft
{
get { return (_paddingLeft / 2f) + _shadowDx; }
set { _paddingLeft = value; }
}
float PaddingTop
{
get { return (_paddingTop / 2f) + _shadowDy; }
set { _paddingTop = value; }
}
double BorderWidth => Math.Max(BorderElement.IsBorderWidthSet() ? BorderElement.BorderWidth : .25, 0);
Color BorderColor => BorderElement.IsBorderColorSet() && BorderElement.BorderColor != Color.Default ? BorderElement.BorderColor : Color.FromHex("#c5c5c5");
public BorderDrawable(Func<double, float> convertToPixels, Color defaultColor, bool drawOutlineWithBackground)
{
_convertToPixels = convertToPixels;
_pressed = false;
_defaultColor = defaultColor;
_drawOutlineWithBackground = drawOutlineWithBackground;
}
public IBorderElement BorderElement
{
get;
set;
}
public override bool IsStateful
{
get { return true; }
}
public override int Opacity
{
get { return 0; }
}
public override void Draw(Canvas canvas)
{
//Bounds = new Rect(Bounds.Left, Bounds.Top, Bounds.Right + (int)_convertToPixels(10), Bounds.Bottom + (int)_convertToPixels(10));
int width = Bounds.Width();
int height = Bounds.Height();
if (width <= 0 || height <= 0)
return;
if (_normalBitmap == null ||
_normalBitmap?.IsDisposed() == true ||
_pressedBitmap?.IsDisposed() == true ||
_normalBitmap.Height != height ||
_normalBitmap.Width != width)
Reset();
if (!_drawOutlineWithBackground && BorderElement.BackgroundColor == Color.Default)
return;
Bitmap bitmap = null;
if (GetState().Contains(global::Android.Resource.Attribute.StatePressed))
{
_pressedBitmap = _pressedBitmap ?? CreateBitmap(true, width, height);
bitmap = _pressedBitmap;
}
else
{
_normalBitmap = _normalBitmap ?? CreateBitmap(false, width, height);
bitmap = _normalBitmap;
}
canvas.DrawBitmap(bitmap, 0, 0, new Paint());
}
public BorderDrawable SetShadow(float dy, float dx, AColor color, float radius)
{
_shadowDx = dx;
_shadowDy = dy;
_shadowColor = color;
_shadowRadius = radius;
return this;
}
public BorderDrawable SetPadding(float top, float left)
{
_paddingTop = top;
_paddingLeft = left;
return this;
}
public void Reset()
{
if (_normalBitmap != null)
{
if (!_normalBitmap.IsDisposed())
{
_normalBitmap.Recycle();
_normalBitmap.Dispose();
}
_normalBitmap = null;
}
if (_pressedBitmap != null)
{
if (!_pressedBitmap.IsDisposed())
{
_pressedBitmap.Recycle();
_pressedBitmap.Dispose();
}
_pressedBitmap = null;
}
}
public override void SetAlpha(int alpha)
{
}
public override void SetColorFilter(ColorFilter cf)
{
}
public Color BackgroundColor => BorderElement.BackgroundColor == Color.Default ? _defaultColor : BorderElement.BackgroundColor;
public Color PressedBackgroundColor => BackgroundColor.AddLuminosity(-.12);//<item name="highlight_alpha_material_light" format="float" type="dimen">0.12</item>
protected override void Dispose(bool disposing)
{
if (_isDisposed)
return;
_isDisposed = true;
if (disposing)
Reset();
base.Dispose(disposing);
}
protected override bool OnStateChange(int[] state)
{
bool old = _pressed;
_pressed = state.Contains(global::Android.Resource.Attribute.StatePressed);
if (_pressed != old)
{
InvalidateSelf();
return true;
}
return false;
}
Bitmap CreateBitmap(bool pressed, int width, int height)
{
Bitmap bitmap = Bitmap.CreateBitmap(width, height, Bitmap.Config.Argb8888);
using (var canvas = new Canvas(bitmap))
{
DrawBackground(canvas, width, height, pressed);
if (_drawOutlineWithBackground)
DrawOutline(canvas, width, height);
}
return bitmap;
}
float ConvertCornerRadiusToPixels()
{
int cornerRadius = DefaultCornerRadius;
if (BorderElement.IsCornerRadiusSet() && BorderElement.CornerRadius != (int)BorderElement.CornerRadiusDefaultValue)
cornerRadius = BorderElement.CornerRadius;
return _convertToPixels(cornerRadius);
}
public RectF GetPaddingBounds(int width, int height)
{
RectF rect = new RectF(0, 0, width, height);
rect.Inset(PaddingLeft, PaddingTop);
return rect;
}
RectF createRect(int width, int height)
{
RectF rect = new RectF(0, 0, width, height);
rect.Inset(PaddingLeft , PaddingTop);
return rect;
}
RectF createRectOutline(int width, int height)
{
RectF rect = new RectF(0, 0, width, height);
float borderWidth = _convertToPixels(BorderWidth);
rect.Inset(PaddingLeft, PaddingTop);
rect.Inset(borderWidth / 2, borderWidth / 2);
return rect;
}
void DrawBackground(Canvas canvas, int width, int height, bool pressed)
{
using (var paint = new Paint { AntiAlias = true })
using (var path = new Path())
{
float borderRadius = Math.Max(ConvertCornerRadiusToPixels(), 0);
RectF rect = createRect(width, height);
float borderWidth = _convertToPixels(BorderWidth);
float inset = borderWidth / 2;
path.AddRoundRect(rect, borderRadius, borderRadius, Path.Direction.Cw);
paint.Color = pressed ? PressedBackgroundColor.ToAndroid() : BackgroundColor.ToAndroid();
paint.SetStyle(Paint.Style.Fill);
paint.SetShadowLayer(_shadowRadius, _shadowDx, _shadowDy, _shadowColor);
canvas.DrawPath(path, paint);
}
}
public void DrawOutline(Canvas canvas, int width, int height)
{
using (var paint = new Paint { AntiAlias = true })
{
float borderWidth = _convertToPixels(BorderElement.BorderWidth);
// adjust border radius so outer edge of stroke is same radius as border radius of background
float borderRadius = Math.Max(ConvertCornerRadiusToPixels(), 0);
borderRadius = (float)borderRadius - (float)borderWidth / 2.0F;
RectF rect = createRectOutline(width, height);
paint.StrokeWidth = borderWidth;
paint.SetStyle(Paint.Style.Stroke);
paint.Color = BorderColor.ToAndroid();
canvas.DrawRoundRect(rect, borderRadius, borderRadius, paint);
}
}
}
}
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