public static void paintImage(
Canvas canvas = null,
Rect rect = null,
Image image = null,
float scale = 1.0f,
ColorFilter colorFilter = null,
BoxFit?fit = null,
Alignment alignment = null,
Rect centerSlice = null,
ImageRepeat repeat = ImageRepeat.noRepeat,
bool flipHorizontally = false,
bool invertColors = false,
FilterQuality filterQuality = FilterQuality.low
)
{
D.assert(canvas != null);
D.assert(rect != null);
D.assert(image != null);
alignment = alignment ?? Alignment.center;
if (rect.isEmpty)
{
return;
}
Size outputSize = rect.size;
Size inputSize = new Size(image.width, image.height);
Offset sliceBorder = null;
if (centerSlice != null)
{
sliceBorder = new Offset(
centerSlice.left + inputSize.width - centerSlice.right,
centerSlice.top + inputSize.height - centerSlice.bottom
);
outputSize -= sliceBorder;
inputSize -= sliceBorder;
}
fit = fit ?? (centerSlice == null ? BoxFit.scaleDown : BoxFit.fill);
D.assert(centerSlice == null || (fit != BoxFit.none && fit != BoxFit.cover),
() => $"centerSlice was used with a BoxFit {fit} that is not supported.");
FittedSizes fittedSizes = FittedSizes.applyBoxFit(fit.Value, inputSize / scale, outputSize);
Size sourceSize = fittedSizes.source * scale;
Size destinationSize = fittedSizes.destination;
if (centerSlice != null)
{
outputSize += sliceBorder;
destinationSize += sliceBorder;
D.assert(sourceSize == inputSize,
() =>
$"centerSlice was used with a BoxFit {fit} that does not guarantee that the image is fully visible.");
}
if (repeat != ImageRepeat.noRepeat && destinationSize == outputSize)
{
repeat = ImageRepeat.noRepeat;
}
Paint paint = new Paint();
if (colorFilter != null)
{
paint.colorFilter = colorFilter;
}
if (sourceSize != destinationSize)
{
paint.filterQuality = filterQuality;
}
paint.invertColors = invertColors;
float halfWidthDelta = (outputSize.width - destinationSize.width) / 2.0f;
float halfHeightDelta = (outputSize.height - destinationSize.height) / 2.0f;
float dx = halfWidthDelta + (flipHorizontally ? -alignment.x : alignment.x) * halfWidthDelta;
float dy = halfHeightDelta + alignment.y * halfHeightDelta;
Offset destinationPosition = rect.topLeft.translate(dx, dy);
Rect destinationRect = destinationPosition & destinationSize;
bool needSave = repeat != ImageRepeat.noRepeat || flipHorizontally;
if (needSave)
{
canvas.save();
}
if (flipHorizontally)
{
float dxInside = -(rect.left + rect.width / 2.0f);
canvas.translate(-dxInside, 0.0f);
canvas.scale(-1.0f, 1.0f);
canvas.translate(dxInside, 0.0f);
}
if (repeat != ImageRepeat.noRepeat)
{
canvas.clipRect(rect);
}
if (centerSlice == null)
{
Rect sourceRect = alignment.inscribe(
sourceSize, Offset.zero & inputSize
);
if (repeat == ImageRepeat.noRepeat)
{
canvas.drawImageRect(image, sourceRect, destinationRect, paint);
}
else
{
foreach (Rect tileRect in _generateImageTileRects(rect, destinationRect, repeat))
{
canvas.drawImageRect(image, sourceRect, tileRect, paint);
}
}
}
else
{
if (repeat == ImageRepeat.noRepeat)
{
canvas.drawImageNine(image, centerSlice, destinationRect, paint);
}
else
{
foreach (Rect tileRect in _generateImageTileRects(rect, destinationRect, repeat))
{
canvas.drawImageNine(image, centerSlice, tileRect, paint);
}
}
}
if (needSave)
{
canvas.restore();
}
}