如何调整图像大小并保持纵横比?
How to resize my image and maintain the aspect ratio?
我正在尝试调整图片大小以适合 640x640 大小并保持纵横比。
例如,如果这是原始图片:http://i.imgur.com/WEMCSyd.jpg
我想这样调整大小:http://i.imgur.com/K2BalOm.jpg保持纵横比(基本上,图像总是在中间,保持纵横比,其余space保持白色)
我试过用 C# 编写一个程序,其中包含以下代码:
Bitmap originalImage, resizedImage;
try
{
using (FileStream fs = new FileStream(textBox1.Text, System.IO.FileMode.Open))
{
originalImage = new Bitmap(fs);
}
int imgHeight = 640;
int imgWidth = 640;
if (originalImage.Height == originalImage.Width)
{
resizedImage = new Bitmap(originalImage, imgHeight, imgWidth);
}
else
{
float aspect = originalImage.Width / (float)originalImage.Height;
int newHeight;
int newWidth;
newWidth = (int)(imgWidth / aspect);
newHeight = (int)(newWidth / aspect);
if (newWidth > imgWidth || newHeight > imgHeight)
{
if (newWidth > newHeight)
{
newWidth = newHeight;
newHeight = (int)(newWidth / aspect);
}
else
{
newHeight = newWidth;
newWidth = (int)(newHeight / aspect);
}
}
resizedImage = new Bitmap(originalImage, newWidth, newHeight);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
但它没有按我需要的方式工作。
你能在图片标签中添加 max-width:100% 吗?并使用 css 定义父标签的固定宽度。希望这应该可以工作,无需为此编写 C# 代码。
Eg. <figure > <img src="" > </figure>
Css
Figure{ width:600px }
Img { max-width: 100%}
设 (W, H)
为您的图片大小。让s = max(W, H)
。然后你想将图像大小调整为 (w, h) = (640 * W / s, 640 * H / s)
其中 /
表示整数除法。请注意,我们有 w <= 640
和 h <= 640
以及 max(w, h) = 640
.
您的图像在新 (640, 640)
图像中的水平和垂直偏移量分别为 x = (640 - W) / 2
和 y = (640 - H) / 2
。
您可以通过创建一个新的 (640, 640)
空白白色图像然后将当前图像绘制到矩形 (x, y, w, h)
.
来完成所有这些操作
var sourcePath = textBox1.Text;
var destinationSize = 640;
using (var destinationImage = new Bitmap(destinationSize, destinationSize))
{
using (var graphics = Graphics.FromImage(destinationImage))
{
graphics.Clear(Color.White);
using (var sourceImage = new Bitmap(sourcePath))
{
var s = Math.Max(sourceImage.Width, sourceImage.Height);
var w = destinationSize * sourceImage.Width / s;
var h = destinationSize * sourceImage.Height / s;
var x = (destinationSize - w) / 2;
var y = (destinationSize - h) / 2;
// Use alpha blending in case the source image has transparencies.
graphics.CompositingMode = CompositingMode.SourceOver;
// Use high quality compositing and interpolation.
graphics.CompositingQuality = CompositingQuality.HighQuality;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.DrawImage(sourceImage, x, y, w, h);
}
}
destinationImage.Save(...);
}
我正在尝试调整图片大小以适合 640x640 大小并保持纵横比。
例如,如果这是原始图片:http://i.imgur.com/WEMCSyd.jpg 我想这样调整大小:http://i.imgur.com/K2BalOm.jpg保持纵横比(基本上,图像总是在中间,保持纵横比,其余space保持白色)
我试过用 C# 编写一个程序,其中包含以下代码:
Bitmap originalImage, resizedImage;
try
{
using (FileStream fs = new FileStream(textBox1.Text, System.IO.FileMode.Open))
{
originalImage = new Bitmap(fs);
}
int imgHeight = 640;
int imgWidth = 640;
if (originalImage.Height == originalImage.Width)
{
resizedImage = new Bitmap(originalImage, imgHeight, imgWidth);
}
else
{
float aspect = originalImage.Width / (float)originalImage.Height;
int newHeight;
int newWidth;
newWidth = (int)(imgWidth / aspect);
newHeight = (int)(newWidth / aspect);
if (newWidth > imgWidth || newHeight > imgHeight)
{
if (newWidth > newHeight)
{
newWidth = newHeight;
newHeight = (int)(newWidth / aspect);
}
else
{
newHeight = newWidth;
newWidth = (int)(newHeight / aspect);
}
}
resizedImage = new Bitmap(originalImage, newWidth, newHeight);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
但它没有按我需要的方式工作。
你能在图片标签中添加 max-width:100% 吗?并使用 css 定义父标签的固定宽度。希望这应该可以工作,无需为此编写 C# 代码。
Eg. <figure > <img src="" > </figure>
Css
Figure{ width:600px }
Img { max-width: 100%}
设 (W, H)
为您的图片大小。让s = max(W, H)
。然后你想将图像大小调整为 (w, h) = (640 * W / s, 640 * H / s)
其中 /
表示整数除法。请注意,我们有 w <= 640
和 h <= 640
以及 max(w, h) = 640
.
您的图像在新 (640, 640)
图像中的水平和垂直偏移量分别为 x = (640 - W) / 2
和 y = (640 - H) / 2
。
您可以通过创建一个新的 (640, 640)
空白白色图像然后将当前图像绘制到矩形 (x, y, w, h)
.
var sourcePath = textBox1.Text;
var destinationSize = 640;
using (var destinationImage = new Bitmap(destinationSize, destinationSize))
{
using (var graphics = Graphics.FromImage(destinationImage))
{
graphics.Clear(Color.White);
using (var sourceImage = new Bitmap(sourcePath))
{
var s = Math.Max(sourceImage.Width, sourceImage.Height);
var w = destinationSize * sourceImage.Width / s;
var h = destinationSize * sourceImage.Height / s;
var x = (destinationSize - w) / 2;
var y = (destinationSize - h) / 2;
// Use alpha blending in case the source image has transparencies.
graphics.CompositingMode = CompositingMode.SourceOver;
// Use high quality compositing and interpolation.
graphics.CompositingQuality = CompositingQuality.HighQuality;
graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
graphics.DrawImage(sourceImage, x, y, w, h);
}
}
destinationImage.Save(...);
}