ASP.NET libwebp.dll如何将WebP映像保存到磁盘 [英] ASP.NET libwebp.dll how to save WebP image to disk

问题描述

我使用

解决方案

我对你的样本也有问题，所以我检查来源，看起来你使用不同的方法然后是样本，不知道为什么。

所以我改变并看起来有效。

 < DllImport（libwebp.dll，CallingConvention： = CallingConvention.Cdecl）GT; 
私有共享函数WebPEncodeBGRA（ByVal rgba As IntPtr，ByVal width As Integer，ByVal height As Integer，ByVal stride As Integer，ByVal quality_factor As Single，< Out> ByRef output as IntPtr）As Integer 
 End函数
 
 
< DllImport（libwebp.dll，CallingConvention：= CallingConvention.Cdecl）> 
私有共享函数WebPFree（ByVal p As IntPtr）As Integer 
结束函数
  

和导入

 导入System.Runtime.InteropServices 
  

我从 Thise说明'libwebp-0.6.0.zip \ x64 \ bin'，它可以工作。

当我从
尝试附加你的dll时，请在这里下载已编译和压缩的libwebp.dll。这是我正在使用的图像文件：

得到完全相同的异常，看起来不是64

对于图像我不确定，可能你需要逆转它

 'data.strinde = webp_data'不确定什么是webp_data ewxacly，但你可以查看
'data.Scan0 = webp_data'不确定什么是webp_data ewxacly，但你可以检查
 source.UnlockBits（data）
 source.Save（Server.MapPath（ images \）+audio.png）
  

I've built libwebp.dll for WebP, using these instructions (I downloaded this source code)

I've added the libwebp.dll file to the bin folder of my project.

I then added this code (found here):

Private Declare Function WebPEncodeBGRA Lib "libwebp.dll" (ByVal rgba As IntPtr, ByVal width As Integer, ByVal height As Integer, ByVal stride As Integer, ByVal quality_factor As Single, ByRef output As IntPtr) As Integer
Private Declare Function WebPFree Lib "libwebp.dll" (ByVal p As IntPtr) As Integer

Private Sub Encode()
    Dim source As Bitmap = New Bitmap(Server.MapPath("images\") + "audio.png")
    Dim data As BitmapData = source.LockBits(New Rectangle(0, 0, source.Width, source.Height), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb)
    Dim webp_data As IntPtr
    Dim i As Integer = WebPEncodeBGRA(data.Scan0, source.Width, source.Height, data.Stride, 80, webp_data)

    WebPFree(webp_data)
End Sub

I get the error:

An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)

What I also did (after comments from Dai below):

• I built the dll for a 64-bit architecture like so: nmake /f Makefile.vc CFG=release-dynamic RTLIBCFG=dynamic OBJDIR=output ARCH=x64 (also see here)
• I checked IIS for the application pool in question and it has the property Enable32-Bit Applications set to False
• I'm running Windows 10 64 bit
• Both Environment.Is64BitProcess and Environment.Is64BitOperatingSystem in code-behind evaluate as True

How can I encode the image and save the encoded image to disk in WebP format?

To test on your machine:
Download the compiled and zipped libwebp.dll here. This is the image file I'm using:

解决方案

i also have problem with yours sample, so i check sources and looks like u use different approach then is in sample, don't know why.

so i change and looks it works.

    <DllImport("libwebp.dll", CallingConvention:=CallingConvention.Cdecl)>
Private Shared Function WebPEncodeBGRA(ByVal rgba As IntPtr, ByVal width As Integer, ByVal height As Integer, ByVal stride As Integer, ByVal quality_factor As Single, <Out> ByRef output As IntPtr) As Integer
End Function


<DllImport("libwebp.dll", CallingConvention:=CallingConvention.Cdecl)>
Private Shared Function WebPFree(ByVal p As IntPtr) As Integer
End Function

and import

Imports System.Runtime.InteropServices

i Have use dll from Download libwebp-0.6.0.zip from Thise instructions 'libwebp-0.6.0.zip\x64\bin' and it works.

When i try attache your dll from Download the compiled and zipped libwebp.dll here. This is the image file I'm using:

got exactly this same exception, looks like is not 64

for image i'm not sure, probaly u need reverse it

            'data.strinde = webp_data 'not sure what is webp_data ewxacly, but you can check
        'data.Scan0 = webp_data 'not sure what is webp_data ewxacly, but you can check
        source.UnlockBits(data)
        source.Save(Server.MapPath("images\") + "audio.png")

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