从缩放的小尺寸图像获取相同的矩形位置 [英] Getting Same Rectangle Position from Scaled Small Size Image

问题描述

我正在尝试处理大尺寸图像.由于处理需要太多时间才能完成，因此我需要在处理之前调整图像的大小.处理后，我在小尺寸图像上绘制了一个矩形.我该如何翻译该矩形与原始未缩放图像的坐标，即:在未缩放图像的相同位置绘制矩形.

I'm trying to process a large size image.Since the processing takes too much time to complete i'm resizing the image prior processing.After processing i'm drawing a rectangle on the small size image.How can i translate the the coordinates of this rectangle to original unscaled image ie:Draw the rectangle at the same position on the unscaled image.

我正在使用以下代码调整图片大小

I'm using the following code to resize the image

public static Size ResizeKeepAspect(Size CurrentDimensions, int maxWidth, int maxHeight)
{
    int newHeight = CurrentDimensions.Height;
    int newWidth = CurrentDimensions.Width;
    if (maxWidth > 0 && newWidth > maxWidth) //WidthResize
    {
        Decimal divider = Math.Abs((Decimal)newWidth / (Decimal)maxWidth);
        newWidth = maxWidth;
        newHeight = (int)Math.Round((Decimal)(newHeight / divider));
    }
    if (maxHeight > 0 && newHeight > maxHeight) //HeightResize
    {
        Decimal divider = Math.Abs((Decimal)newHeight / (Decimal)maxHeight);
        newHeight = maxHeight;
        newWidth = (int)Math.Round((Decimal)(newWidth / divider));
    }
    return new Size(newWidth, newHeight);
}

这就是我要实现的目标

推荐答案

Rectangle ConvertToLargeRect(Rectangle smallRect, Size largeImageSize, Size smallImageSize)
{
    double xScale = (double)largeImageSize.Width / smallImageSize.Width;
    double yScale = (double)largeImageSize.Height / smallImageSize.Height;    
    int x = (int)(smallRect.X * xScale + 0.5);
    int y = (int)(smallRect.Y * yScale + 0.5);
    int right = (int)(smallRect.Right * xScale + 0.5);
    int bottom = (int)(smallRect.Bottom * yScale + 0.5);
    return new Rectangle(x, y, right - x, bottom - y);
}

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