Check if bitmap pixel data contains alpha information.

While reading this topic Image.GetFlags method  (the topic was written in C language) , I came with  a solution to check if the bitmap or image pixel data contains alpha information,

In Dot Net to gets flags that indicate certain attributes of an Image , simply check the value of Flags property which will return a bitwise combination of ImageFlags.

The following Function shows how to check bitmap alpha information.

 Code:

     Public Shared Function IsHasAlpha(bmp As Bitmap) As Boolean
        Return bmp IsNot Nothing AndAlso (bmp.Flags And Imaging.ImageFlags.HasAlpha) > Imaging.ImageFlags.None
    End Function

 Usage:

 1 - Define a bitmap.
2 - Pass the bitmap value to the above function, and if the image has alpha information the function  shall returned True
  
  If IsHasAlpha(bmp) Then
    ' Do something
  End If

References:

GetFlags Method
Image Flags Property
ImageFlags Enumeration

Comments

Post a Comment

Popular posts from this blog

مقدمة الي تشفير الحروف الأبجدية العربية

مقدمة الحروف العربية مظلومة قليلا و غاليا اي مبرمج يعاني أحيانا في التعامل مع الحروف العربية تحديدا او قد يعاني أيضا حين  يريد التعامل مع اي حروف مكتوبة بلغة أخري غير اللغة الإنجليزية و في هذا الموضوح سأحاول أن أوضح كيفية تشفير الحروف العربية فقط الفكرة الحروف بشكل عام لها جداول وداخل هذه الجداول ستجد أن الحروف مرتبة برقم مسلسل و ايضا لها رقم  سداسي عشري  أو بمعني أدق كل حرف في جداول الحروف له مميزات يتم استخدامها للتفريق بينه و بين باق الحروف الأمثلة التالية توضح كيفية الحصول علي الرقم المسلسل الخاص بأي حرف مثال 1: الكود التالي يوضح مثال بسيط لكيفية الحصول علي الرقم المسلسل الخاص بحرف الياء التي تحتها نقطتان Dim c  As  Char  =  "ي" c Me . Text  =  Convert . ToInt32 ( c ) مثال 2: أيضا الكود التالي يوضح كيفية الحصول علي الرقم المسلسل الخاص بحرف الهمزة Dim c  As  Char  =  "ء" c Me . Text  =  Convert . ToInt32 ( c ) من الأمثلة أعلاه ستكتشف ان الرقم المسلسل بالحروف العربية يبدأ من الرقم 1569 , وينتهي بالرقم 1610 الملحوظة الهامة هنا هي أن الرقم
Read more

VB.NET Translucent Control using GDI+

Image
Introduction The main purpose of this article is to show how to build your own Transparent Control in VB.NET by extending the control through inheritance . Also, the class might be used as a base class to build your own custom transparent controls such as PictureBox , Button , Panel , .....etc. Background Since the Windows Form Control is the only control that supports transparency through its Opacity property, I decided to utilize the same strategy to build a control that supports transparency. I saw so many articles talks about the transparency of the control, and I had studied most of the techniques which discuss the same issue and some of these techniques are listed below: To call InvokePaintBackground of the control’s parent and override the OnPaintBackground event. To draw image which supports transparency to avoid the issues due to double buffering and flickering? To override CreateParams property, set ExStyle value to support transparency and on OnPa
Read more

Add Custom Event to a Class in VB.NET

Introduction This article demonstrates how to add a Custom Event to a Class in VB.NET and use it by any means in your code. On January 2010, I wrote an article in Arabic language about how to handle Custom Event in VB.NET either within a Class or within a Component/Control and I would like to share the same thoughts with my CodeProject colleagues. It might be helpful for somebody. Background According to MSDN to handle an Event or more than an Event, the following procedures shall be followed: Define a delegate collection within the class that raises the events. Define a key for each event. Define the event properties in the class that raises the events. Use the delegate collection to implement add and remove accessor methods for the event properties. Use the public event properties to add and remove event handler delegates in the classes that handle the events. Actually adding or handling a Public Event within a Class is a very simple issue, but handling a Custom Eve
Read more