How to draw/ realize lines with the right thickness (1.5f)

Question

Hi,
how can i archieve it?
I'm using my own Scrollbar Renderer and i've tried to draw the arrow like in the windows calculator

by DrawLines but it's not working because there is no difference in 1 and 1.5f by GDI drawing as mentioned here:
https://stackoverflow.com/questions/45139526/how-to-change-the-thickness-of-the-line-drawn-using-system-drawing-pen

(I guess i need 1.5f because 1 is to thin and 2 is far too big)

I've also tried to draw and resize a bitmap but that looks blurry, sizing to the right size is not that easy and i assume that this won't solve it.

Should i draw by a graphic program? Is there an online tool to draw it easily by coordinates and pixel for the thickness? (I've tried it with inscape that doesn't seem to work. I can't enter one-digit values for all values, it's getting changed by the program.)

DrawLine:

  upArrowPoints = new Point[]{  
                            new Point(5, 10),  
                            new Point(8, 7),  
                             new Point(9, 7),  
                            new Point(12,10)};  
  
                using (var pen = new Pen(arrowColor,1.0f))  
                {  
                    e.Graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;  
                    e.Graphics.DrawLines(pen, upArrowPoints);  
                }  

Draw to bitmap:

        bitmapUpArrow = new Bitmap(6, 4);  

        using (Graphics gr = Graphics.FromImage(bitmapUpArrow))  
        {  
            gr.SmoothingMode = SmoothingMode.AntiAlias;  

            using (Pen thick_pen = new Pen(Color.Red, 1))  
            {  
                gr.DrawLine(thick_pen, 0, 3, 2, 0);  
                gr.DrawLine(thick_pen, 3, 0, 5, 3);  
            }  
        }  

Tried several resizing solutions:
https://stackoverflow.com/questions/1922040/how-to-resize-an-image-c-sharp

Answer 1

Scrollbar arrows are drawn by Theme APIs

A quick test on the main window DC :

int nX = 10;  
int nY = 200;  
RECT rectTest = new RECT(nX, nY, nX + 30, nY + 30);                 
IntPtr hTheme = OpenThemeData(this.Handle, "ScrollBar");  
if (hTheme != IntPtr.Zero)  
{  
    IntPtr hDC = GetDC(this.Handle);  
    DrawThemeBackground(hTheme, hDC, (int)SCROLLBARPARTS.SBP_ARROWBTN, (int)ARROWBTNSTATES.ABS_UPNORMAL, ref rectTest, IntPtr.Zero);  
    rectTest.left += 40;  
    rectTest.right += 40;  
    DrawThemeBackground(hTheme, hDC, (int)SCROLLBARPARTS.SBP_ARROWBTN, (int)ARROWBTNSTATES.ABS_UPHOT, ref rectTest, IntPtr.Zero);  
    rectTest.left += 40;  
    rectTest.right += 40;  
    DrawThemeBackground(hTheme, hDC, (int)SCROLLBARPARTS.SBP_ARROWBTN, (int)ARROWBTNSTATES.ABS_UPPRESSED, ref rectTest, IntPtr.Zero);  
    CloseThemeData(hTheme);  
    ReleaseDC(this.Handle, hDC);  
}  

with declarations :

    [DllImport("UxTheme.dll", SetLastError = true, CharSet = CharSet.Unicode)]  
    public static extern IntPtr OpenThemeData(IntPtr hwnd, string pszClassList);  

    [DllImport("UxTheme.dll", SetLastError = true)]  
    public static extern IntPtr GetWindowTheme(IntPtr hwnd);  

    [DllImport("UxTheme.dll", SetLastError = true)]  
    public static extern HRESULT CloseThemeData(IntPtr hTheme);  

    [DllImport("UxTheme.dll", SetLastError = true)]  
    public extern static HRESULT DrawThemeBackground(IntPtr hTheme, IntPtr hdc, int iPartId, int iStateId, ref RECT pRect, IntPtr pClipRect);  

    public enum SCROLLBARPARTS  
    {  
        SBP_ARROWBTN = 1,  
        SBP_THUMBBTNHORZ = 2,  
        SBP_THUMBBTNVERT = 3,  
        SBP_LOWERTRACKHORZ = 4,  
        SBP_UPPERTRACKHORZ = 5,  
        SBP_LOWERTRACKVERT = 6,  
        SBP_UPPERTRACKVERT = 7,  
        SBP_GRIPPERHORZ = 8,  
        SBP_GRIPPERVERT = 9,  
        SBP_SIZEBOX = 10,  
        SBP_SIZEBOXBKGND = 11,  
    };  

    public enum ARROWBTNSTATES  
    {  
        ABS_UPNORMAL = 1,  
        ABS_UPHOT = 2,  
        ABS_UPPRESSED = 3,  
        ABS_UPDISABLED = 4,  
        ABS_DOWNNORMAL = 5,  
        ABS_DOWNHOT = 6,  
        ABS_DOWNPRESSED = 7,  
        ABS_DOWNDISABLED = 8,  
        ABS_LEFTNORMAL = 9,  
        ABS_LEFTHOT = 10,  
        ABS_LEFTPRESSED = 11,  
        ABS_LEFTDISABLED = 12,  
        ABS_RIGHTNORMAL = 13,  
        ABS_RIGHTHOT = 14,  
        ABS_RIGHTPRESSED = 15,  
        ABS_RIGHTDISABLED = 16,  
        ABS_UPHOVER = 17,  
        ABS_DOWNHOVER = 18,  
        ABS_LEFTHOVER = 19,  
        ABS_RIGHTHOVER = 20,  
    };  
      
    [StructLayout(LayoutKind.Sequential)]  
    public struct RECT  
    {  
        public int left;  
        public int top;  
        public int right;  
        public int bottom;  
        public RECT(int Left, int Top, int Right, int Bottom)  
        {  
            left = Left;  
            top = Top;  
            right = Right;  
            bottom = Bottom;  
        }  
    }  
      
   [DllImport("User32", ExactSpelling = true, CharSet = CharSet.Auto)]  
   public static extern IntPtr GetDC(IntPtr hWnd);  

   [DllImport("User32", ExactSpelling = true, CharSet = CharSet.Auto)]  
   public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);  

Answer 2

Hi Castorix,
after a second look, i realized it's really that (system) arrow but much thinner.
Is it possible to make it thinner that it looks like in a WPF/ Win10 default scrollbar?

(I would like to use it also in a context menu later, if i can, for a uniform look )

If it's possible to look like a WPF scrollbar, have you used your code with a VScrollBar?

Answer 3

Could anybody explain, what he means?

What can i do with this code?
Doesn't do anything with a VScrollbar?
Doesn't have any effect here!