public async Task <bool> WriteAndCropFile(string fileHash,
OffsetModel offsetData, int sourceWidth,
int sourceHeight, FileIndexItem.Rotation rotation,
string reference = null)
{
try
{
using (var thumbnailStream = new MemoryStream(offsetData.Data, offsetData.Index, offsetData.Count))
using (var smallImage = await Image.LoadAsync(thumbnailStream))
using (var outputStream = new MemoryStream())
{
var smallImageWidth = smallImage.Width;
var smallImageHeight = smallImage.Height;
var result = NewImageSize.NewImageSizeCalc(smallImageWidth,
smallImageHeight, sourceWidth, sourceHeight);
smallImage.Mutate(
i => i.Resize(smallImageWidth, smallImageHeight, KnownResamplers.Lanczos3)
.Crop(new Rectangle(result.DestX, result.DestY, result.DestWidth, result.DestHeight)));
var larger = (int)Math.Round(result.DestWidth * 1.2, 0);
smallImage.Mutate(
i => i.Resize(larger, 0, KnownResamplers.Lanczos3));
var rotate = RotateEnumToDegrees(rotation);
smallImage.Mutate(
i => i.Rotate(rotate));
await smallImage.SaveAsJpegAsync(outputStream);
await _thumbnailStorage.WriteStreamAsync(outputStream, ThumbnailNameHelper.Combine(fileHash, ThumbnailSize.TinyMeta));
if (_appSettings.ApplicationType == AppSettings.StarskyAppType.WebController)
{
_logger.LogInformation($"[WriteAndCropFile] fileHash: {fileHash} is written");
}
}
return(true);
}
catch (Exception ex)
{
var message = ex.Message;
if (message.StartsWith("Image cannot be loaded"))
{
message = "Image cannot be loaded";
}
_logger.LogError($"[WriteFile@meta] Exception {reference} {message}", ex);
return(false);
}
}
public void NewImageSize_Portrait()
{
var sourceWidth = 2832;
var sourceHeight = 4240;
var smallWidth = 120;
var smallHeight = 160;
var rNewImageSizeCalc = NewImageSize.NewImageSizeCalc(smallWidth,
smallHeight, sourceWidth, sourceHeight);
Assert.AreEqual(160, rNewImageSizeCalc.DestHeight);
Assert.AreEqual(106, rNewImageSizeCalc.DestWidth);
Assert.AreEqual(7, rNewImageSizeCalc.DestX);
Assert.AreEqual(0, rNewImageSizeCalc.DestY);
}
/// <summary>
/// 指定大小简单等比缩放图片
/// </summary>
/// <param name="original_image"></param>
/// <param name="new_width"></param>
/// <returns></returns>
//public static Bitmap GetSimpleThumbnailImage(Image original_image, int new_width, int new_height)
//{
// NewImageSize imageSize = new NewImageSize(original_image.Width, original_image.Height, new_width, new_height);
// Bitmap returnImage = null;
// returnImage = new Bitmap(original_image, imageSize.NewWidth, imageSize.NewHeight);
// return returnImage;
//}
/// <summary>
/// 根据指定大小绘制高质量缩略图
/// </summary>
/// <param name="original_image"></param>
/// <param name="new_width"></param>
/// <returns></returns>
public static Bitmap GetThumbnailImage(Image original_image, ThumbnailImageType titCase, int target_width, int target_height)
{
System.Drawing.Graphics graphic = null;
Bitmap returnImage = null;
int origin_width = original_image.Width;
int origin_height = original_image.Height;
int paste_x = 0, paste_y = 0;
NewImageSize imageSize = new NewImageSize(original_image.Width, original_image.Height, target_width, target_height);
int new_width = imageSize.NewWidth, new_height = imageSize.NewHeight;
target_width = imageSize.NewWidth;
target_height = imageSize.NewHeight;
float origin_ratio = imageSize.OrignRatio;
float target_ratio = imageSize.NewRatio;
//缩略图生成方式
switch (titCase)
{
//缩放全图到正确比例
case ThumbnailImageType.Zoom:
if (target_ratio > origin_ratio)
{
//较宽图片
new_height = (int)Math.Floor((float)target_width / origin_ratio);
new_width = target_width;
}
else
{
//较高图片
new_height = target_height;
new_width = (int)Math.Floor(origin_ratio * (float)target_height);
}
new_width = new_width > target_width ? target_width : new_width;
new_height = new_height > target_height ? target_height : new_height;
break;
//截取高宽比中间部分
case ThumbnailImageType.Cut:
if (target_ratio > origin_ratio)
{
//较高图片
new_height = (int)Math.Floor((float)target_width / origin_ratio);
new_width = target_width;
}
else
{
//较宽图片
new_height = target_height;
new_width = (int)Math.Floor(origin_ratio * (float)target_height);
}
break;
}
paste_x = (target_width - new_width) / 2;
paste_y = (target_height - new_height) / 2;
// 创建缩略图
returnImage = new System.Drawing.Bitmap(target_width, target_height);
graphic = System.Drawing.Graphics.FromImage(returnImage);
//指定画布大小并以透明色填充空余部分
graphic.FillRectangle(new System.Drawing.SolidBrush(System.Drawing.Color.White), new System.Drawing.Rectangle(0, 0, target_width, target_height));
//设置高质量绘画
graphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
graphic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//输出缩略图
graphic.DrawImage(original_image, paste_x, paste_y, new_width, new_height);
return(returnImage);
}