Question

我正在创建一个加载2个图像的方法，对它们应用一些转换（缩放/旋转），然后使用.NET Graphics类在另一个图像上的某个点上绘制它们。

我目前正在尝试的流程如下：

Load bmp1
Load bmp2
Create graphics object from bmp1
Apply tranformations
Save
Repeat process for bmp2
Instantiate new merged bmp obj
Create graphics object from merged bmp
Draw bmp1 & bmp2 on merged bmp
Save

我正尝试使用以下代码执行此操作：

// load existing bmps
var bmp1 = new Bitmap(Path.Combine(_staticIconsPath, staticIcon.Filename));
var bmp2 = new Bitmap(Path.Combine(_movableIconsPath, movableIcon.Filename));

// apply transforms to bmp1
var canvas1 = Graphics.FromImage(bmp1);
canvas1.ScaleTransform(0.5f, 0.5f);
canvas1.RotateTransform(45.0f);
canvas1.Save();

// apply transforms to bmp2
var canvas2 = Graphics.FromImage(bmp2);
canvas2.ScaleTransform(0.5f, 0.5f);
canvas2.RotateTransform(45.0f);
canvas2.Save();

// create final merged bmp
var mergedBmp = new Bitmap(590, 590);
mergedBmp.SetResolution(bmp1.HorizontalResolution, bmp1.VerticalResolution);

// draw transformed images on to final bmp
var mergedCanvas = Graphics.FromImage(mergedBmp);
mergedCanvas.DrawImage(bmp1, 0, 0);
mergedCanvas.DrawImage(bmp2, 0, 0);

mergedCanvas.Save();

然而，最终结果只是加载的两个原始位图，两者都按预期绘制在彼此之上，但没有应用变换。

我之前从未使用过GDI或进行任何图像处理，所以我认为我误解了必须遵循的过程的基本内容。任何人都可以帮助我并指出我正确的方向吗？

Answer 1

你必须在每个bmp文件中保存名为canevas的转换。您可以使用这些bmp来绘制合并的文件。但是不要设置相同的位置当drawingImage，因为在同一位置的两个图像，你只会看到一个，最后一个。

            // load existing bmps 
        var bmp1 = new Bitmap("test2.bmp");
        var bmp2 = new Bitmap("test2.bmp");

        // apply transforms to bmp1 
        var canvas1 = Graphics.FromImage(bmp1);
        canvas1.ScaleTransform(0.5f, 0.5f);
        canvas1.RotateTransform(45.0f);
        canvas1.Save();
        canvas1.DrawImage(bmp1,100, 0);
        bmp1.Save("test1res.bmp");
        var bmpres1 = new Bitmap("test1res.bmp");

        // apply transforms to bmp2
        var resbmp2 = new Bitmap(1000, 1000);
        var canvas2 = Graphics.FromImage(bmp2);
        canvas2.ScaleTransform(0.5f, 0.5f);
        canvas2.RotateTransform(45.0f);
        canvas2.Save();
        canvas2.DrawImage(bmp2, 100, 0);
        bmp2.Save("test2res.bmp");
        var bmpres2 = new Bitmap("test2res.bmp");

        // create final merged bmp 
        var mergedBmp = new Bitmap(1000, 1000);
        mergedBmp.SetResolution(bmp1.HorizontalResolution, bmp1.VerticalResolution);

        // draw transformed images on to final bmp 
        var mergedCanvas = Graphics.FromImage(mergedBmp);
        mergedCanvas.DrawImage(bmpres1, 0, 0);
        mergedCanvas.DrawImage(bmpres2, 500, 0);

        mergedCanvas.Save();
        Graphics graph = mergedCanvas;
       // Bitmap bmpPicture = new Bitmap("test2.bmp");
        graph.DrawImage(mergedBmp, 0, 0);

        mergedBmp.Save("res.bmp");

Answer 2

是的，你做错了。除非您实际使用它绘制，否则Graphics对象修改无效。你没有，你只用mergedCanvas绘制。因此，重新订购代码，类似于：

var mergedBmp = new Bitmap(590, 590);
using (var bmp1 = new Bitmap(Path.Combine(_staticIconsPath, staticIcon.Filename)))
using (var bmp2 = new Bitmap(Path.Combine(_movableIconsPath, movableIcon.Filename)))
using (var mergedCanvas = Graphics.FromImage(mergedBmp)) {
    mergedCanvas.Save();
    mergedCanvas.ScaleTransform(0.5f, 0.5f);
    mergedCanvas.DrawImage(bmp1, 0, 0);
    mergedCanvas.Restore();
    mergedCanvas.ScaleTransform(-0.5f, -0.5f);
    mergedCanvas.DrawImage(bmp2, 0, 0);
}

请勿跳过那些使用语句的 btw，这对位图非常重要。

使用GDI和.NET应用转换和组合位图

2 个答案: