如何创建透明位图图像?当我设置属性 Graphics.clear(color.Transparent ) 时,它会给出黑色背景。)
我在名为 displayImage.aspx 的 aspx 页面中使用一个标记,并分配其 src 属性值,该值是另一个名为 getImageFromText.aspx 的 aspx 页面
** src="getImageFromText.aspx" .**
我编写了在 getImageFromText 中创建位图的代码。 aspx.cs 并将其保存在内存蒸汽中,但我无法使该图像透明。当我设置 Graphics.clear(color.Transparent) 时,它会给出黑色背景tats yi 必须设置 Graphics.clear(color.ANYCOLOR) 删除黑色背景。 请给我建议或任何可以为位图图像制作透明背景的代码。
代码如下
protected void Page_Load(object sender, EventArgs e) {
if (Request.QueryString["phone"] != null)
{
CreateBitmapImage(Request.QueryString["phone"]);
}
// CreateBitmapImage("Call Now 123-457-1222");
}
private void CreateBitmapImage(string phonenumber)
{
string message = "Call Now " + phonenumber.ToString();
Bitmap objBmpImage = new Bitmap(1, 1);
int intWidth = 0;
int intHeight = 0;
// Create the Font object for the image text drawing.
FontFamily[] fontFamilies;
PrivateFontCollection fontCollection = new PrivateFontCollection();
fontCollection.AddFontFile(Server.MapPath("Futura-Condensed-Bold.ttf"));
fontFamilies = fontCollection.Families;
string familyName = "";
familyName = fontFamilies[0].Name;
Font objFont = new Font(familyName, 19, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Pixel);
// Create a graphics object to measure the text's width and height.
Graphics objGraphics = Graphics.FromImage(objBmpImage);
// This is where the bitmap size is determined.
intWidth = (int)objGraphics.MeasureString(message, objFont).Width;
intHeight = (int)objGraphics.MeasureString(message, objFont).Height;
// Create the bmpImage again with the correct size for the text and font.
objBmpImage = new Bitmap(objBmpImage, new Size(intWidth, intHeight));
// Add the colors to the new bitmap.
objGraphics = Graphics.FromImage(objBmpImage);
// Set Background color "#5496CA"
string xCol = "#5496CA";
Color clearClr = System.Drawing.ColorTranslator.FromHtml(xCol);
objGraphics.Clear(clearClr);
objGraphics.SmoothingMode = SmoothingMode.AntiAlias;
objGraphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
objGraphics.TextRenderingHint = TextRenderingHint.AntiAlias;
objGraphics.DrawString(message, objFont, new SolidBrush(Color.White), 0, 0);
MemoryStream memoryStream = new MemoryStream();
objBmpImage.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Bmp);
// Write the MemoryStream to the Response stream, and set content type to image/gif.
memoryStream.WriteTo(Response.OutputStream);
Response.ContentType = "image/gif";
Response.End();
// Clean up.
memoryStream.Close();
objGraphics.Flush();
}
I am using a tag in a aspx page named displayImage.aspx and assigning its src attribute value which is other one aspx page named getImageFromText.aspx
** src="getImageFromText.aspx" .**
I wrote code for creating bitmap in getImageFromText.aspx.cs and saving it in memory steam but i am not able to make that image transparent .When i set Graphics.clear(color.Transparent) then it gives black background tats y i have to set
Graphics.clear(color.ANYCOLOR) to remove that black background.
Please give me advice or any code from that i can make transparent background for bitmap image .
The code is below
protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString["phone"] != null)
{
CreateBitmapImage(Request.QueryString["phone"]);
}
// CreateBitmapImage("Call Now 123-457-1222");
}
private void CreateBitmapImage(string phonenumber)
{
string message = "Call Now " + phonenumber.ToString();
Bitmap objBmpImage = new Bitmap(1, 1);
int intWidth = 0;
int intHeight = 0;
// Create the Font object for the image text drawing.
FontFamily[] fontFamilies;
PrivateFontCollection fontCollection = new PrivateFontCollection();
fontCollection.AddFontFile(Server.MapPath("Futura-Condensed-Bold.ttf"));
fontFamilies = fontCollection.Families;
string familyName = "";
familyName = fontFamilies[0].Name;
Font objFont = new Font(familyName, 19, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Pixel);
// Create a graphics object to measure the text's width and height.
Graphics objGraphics = Graphics.FromImage(objBmpImage);
// This is where the bitmap size is determined.
intWidth = (int)objGraphics.MeasureString(message, objFont).Width;
intHeight = (int)objGraphics.MeasureString(message, objFont).Height;
// Create the bmpImage again with the correct size for the text and font.
objBmpImage = new Bitmap(objBmpImage, new Size(intWidth, intHeight));
// Add the colors to the new bitmap.
objGraphics = Graphics.FromImage(objBmpImage);
// Set Background color "#5496CA"
string xCol = "#5496CA";
Color clearClr = System.Drawing.ColorTranslator.FromHtml(xCol);
objGraphics.Clear(clearClr);
objGraphics.SmoothingMode = SmoothingMode.AntiAlias;
objGraphics.PixelOffsetMode = PixelOffsetMode.HighQuality;
objGraphics.TextRenderingHint = TextRenderingHint.AntiAlias;
objGraphics.DrawString(message, objFont, new SolidBrush(Color.White), 0, 0);
MemoryStream memoryStream = new MemoryStream();
objBmpImage.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Bmp);
// Write the MemoryStream to the Response stream, and set content type to image/gif.
memoryStream.WriteTo(Response.OutputStream);
Response.ContentType = "image/gif";
Response.End();
// Clean up.
memoryStream.Close();
objGraphics.Flush();
}
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使用:
Bitmap.MakeTransparent,通过使用类似一个参数,一个您希望变得透明的颜色。
问候。
Use:
Bitmap.MakeTransparent, by using like a parameter a color you wish to become transparent.
Regards.