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//------------------------------------------------------------------------------
// <copyright file="GroupBoxRenderer.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Windows.Forms {
using System;
using System.Drawing;
using System.Windows.Forms.Internal;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Windows.Forms.VisualStyles;
using Microsoft.Win32;
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer"]/*' />
/// <devdoc>
/// <para>
/// This is a rendering class for the GroupBox control.
/// </para>
/// </devdoc>
public sealed class GroupBoxRenderer {
//Make this per-thread, so that different threads can safely use these methods.
[ThreadStatic]
private static VisualStyleRenderer visualStyleRenderer = null;
private static readonly VisualStyleElement GroupBoxElement = VisualStyleElement.Button.GroupBox.Normal;
private const int textOffset = 8; //MAGIC NUMBER - WHERE DID IT COME FROM?
private const int boxHeaderWidth = 7; // VSWhidbey 514912: The groupbox frame shows 7 pixels before the caption.
private static bool renderMatchingApplicationState = true;
//cannot instantiate
private GroupBoxRenderer() {
}
/// <include file='doc\ButtonRenderer.uex' path='docs/doc[@for="ButtonRenderer.RenderMatchingApplicationState"]/*' />
/// <devdoc>
/// <para>
/// If this property is true, then the renderer will use the setting from Application.RenderWithVisualStyles to
/// determine how to render.
/// If this property is false, the renderer will always render with visualstyles.
/// </para>
/// </devdoc>
public static bool RenderMatchingApplicationState {
get {
return renderMatchingApplicationState;
}
set {
renderMatchingApplicationState = value;
}
}
private static bool RenderWithVisualStyles {
get {
return (!renderMatchingApplicationState || Application.RenderWithVisualStyles);
}
}
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer.IsBackgroundPartiallyTransparent"]/*' />
/// <devdoc>
/// <para>
/// Returns true if the background corresponding to the given state is partially transparent, else false.
/// </para>
/// </devdoc>
public static bool IsBackgroundPartiallyTransparent(GroupBoxState state) {
if (RenderWithVisualStyles) {
InitializeRenderer((int)state);
return visualStyleRenderer.IsBackgroundPartiallyTransparent();
}
else {
return false; //for downlevel, this is false
}
}
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer.DrawParentBackground"]/*' />
/// <devdoc>
/// <para>
/// This is just a convenience wrapper for VisualStyleRenderer.DrawThemeParentBackground. For downlevel,
/// this isn't required and does nothing.
/// </para>
/// </devdoc>
[
SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters") // Using Graphics instead of IDeviceContext intentionally
]
public static void DrawParentBackground(Graphics g, Rectangle bounds, Control childControl) {
if (RenderWithVisualStyles) {
InitializeRenderer(0);
visualStyleRenderer.DrawParentBackground(g, bounds, childControl);
}
}
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer.DrawGroupBox"]/*' />
/// <devdoc>
/// <para>
/// Renders a GroupBox control.
/// </para>
/// </devdoc>
public static void DrawGroupBox(Graphics g, Rectangle bounds, GroupBoxState state) {
if (RenderWithVisualStyles)
DrawThemedGroupBoxNoText(g, bounds, state);
else
DrawUnthemedGroupBoxNoText(g, bounds, state);
}
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer.DrawGroupBox1"]/*' />
/// <devdoc>
/// <para>
/// Renders a GroupBox control. Uses the text color specified by the theme.
/// </para>
/// </devdoc>
public static void DrawGroupBox(Graphics g, Rectangle bounds, string groupBoxText, Font font, GroupBoxState state) {
DrawGroupBox(g, bounds, groupBoxText, font, TextFormatFlags.Top | TextFormatFlags.Left, state);
}
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer.DrawGroupBox2"]/*' />
/// <devdoc>
/// <para>
/// Renders a GroupBox control.
/// </para>
/// </devdoc>
public static void DrawGroupBox(Graphics g, Rectangle bounds, string groupBoxText, Font font, Color textColor, GroupBoxState state) {
DrawGroupBox(g, bounds, groupBoxText, font, textColor, TextFormatFlags.Top | TextFormatFlags.Left, state);
}
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer.DrawGroupBox3"]/*' />
/// <devdoc>
/// <para>
/// Renders a GroupBox control. Uses the text color specified by the theme.
/// </para>
/// </devdoc>
public static void DrawGroupBox(Graphics g, Rectangle bounds, string groupBoxText, Font font, TextFormatFlags flags, GroupBoxState state) {
if (RenderWithVisualStyles)
DrawThemedGroupBoxWithText(g, bounds, groupBoxText, font, DefaultTextColor(state), flags, state);
else
DrawUnthemedGroupBoxWithText(g, bounds, groupBoxText, font, DefaultTextColor(state), flags, state);
}
/// <include file='doc\GroupBoxRenderer.uex' path='docs/doc[@for="GroupBoxRenderer.DrawGroupBox4"]/*' />
/// <devdoc>
/// <para>
/// Renders a GroupBox control.
/// </para>
/// </devdoc>
public static void DrawGroupBox(Graphics g, Rectangle bounds, string groupBoxText, Font font, Color textColor, TextFormatFlags flags, GroupBoxState state) {
if (RenderWithVisualStyles)
DrawThemedGroupBoxWithText(g, bounds, groupBoxText, font, textColor, flags, state);
else
DrawUnthemedGroupBoxWithText(g, bounds, groupBoxText, font, textColor, flags, state);
}
/// <summary>
/// Draws a themed GroupBox with no text label.
/// </summary>
/// <internalonly/>
private static void DrawThemedGroupBoxNoText(Graphics g, Rectangle bounds, GroupBoxState state) {
InitializeRenderer((int)state);
visualStyleRenderer.DrawBackground(g, bounds);
}
/// <summary>
/// Draws a themed GroupBox with a text label.
/// </summary>
/// <internalonly/>
private static void DrawThemedGroupBoxWithText(Graphics g, Rectangle bounds, string groupBoxText, Font font, Color textColor, TextFormatFlags flags, GroupBoxState state) {
InitializeRenderer((int)state);
// Calculate text area, and render text inside it
Rectangle textBounds = bounds;
textBounds.Width -= 2 * boxHeaderWidth;
Size measuredBounds = TextRenderer.MeasureText(g, groupBoxText, font, new Size(textBounds.Width, textBounds.Height), flags);
textBounds.Width = measuredBounds.Width;
textBounds.Height = measuredBounds.Height;
if ((flags & TextFormatFlags.Right) == TextFormatFlags.Right) {
textBounds.X = bounds.Right - textBounds.Width - boxHeaderWidth + 1; // +1 to account for the margin built in the MeasureText result
}
else {
textBounds.X += boxHeaderWidth - 1; // -1 to account for the margin built in the MeasureText result
}
TextRenderer.DrawText(g, groupBoxText, font, textBounds, textColor, flags);
// Calculate area for background box
Rectangle boxBounds = bounds;
boxBounds.Y += font.Height / 2;
boxBounds.Height -= font.Height / 2;
// Break box into three segments, that don't overlap the text area
Rectangle clipLeft = boxBounds;
Rectangle clipMiddle = boxBounds;
Rectangle clipRight = boxBounds;
clipLeft.Width = boxHeaderWidth;
clipMiddle.Width = Math.Max(0, textBounds.Width - 3); // -3 to account for the margin built in the MeasureText result
if ((flags & TextFormatFlags.Right) == TextFormatFlags.Right)
{
clipLeft.X = boxBounds.Right - boxHeaderWidth;
clipMiddle.X = clipLeft.Left - clipMiddle.Width;
clipRight.Width = clipMiddle.X - boxBounds.X;
}
else
{
clipMiddle.X = clipLeft.Right;
clipRight.X = clipMiddle.Right;
clipRight.Width = boxBounds.Right - clipRight.X;
}
clipMiddle.Y = textBounds.Bottom;
clipMiddle.Height -= (textBounds.Bottom - boxBounds.Top);
Debug.Assert(textBounds.Y <= boxBounds.Y, "if text below box, need to render area of box above text");
// Render clipped portion of background in each segment
visualStyleRenderer.DrawBackground(g, boxBounds, clipLeft);
visualStyleRenderer.DrawBackground(g, boxBounds, clipMiddle);
visualStyleRenderer.DrawBackground(g, boxBounds, clipRight);
}
/// <summary>
/// Draws an un-themed GroupBox with no text label.
/// </summary>
/// <internalonly/>
private static void DrawUnthemedGroupBoxNoText(Graphics g, Rectangle bounds, GroupBoxState state) {
Color backColor = SystemColors.Control;
Pen light = new Pen(ControlPaint.Light(backColor, 1.0f));
Pen dark = new Pen(ControlPaint.Dark(backColor, 0f));
try {
// left
g.DrawLine(light, bounds.Left + 1, bounds.Top + 1, bounds.Left + 1, bounds.Height - 1);
g.DrawLine(dark, bounds.Left, bounds.Top + 1, bounds.Left, bounds.Height - 2);
// bottom
g.DrawLine(light, bounds.Left, bounds.Height - 1, bounds.Width - 1, bounds.Height - 1);
g.DrawLine(dark, bounds.Left, bounds.Height - 2, bounds.Width - 1, bounds.Height - 2);
// top
g.DrawLine(light, bounds.Left + 1, bounds.Top + 1, bounds.Width - 1, bounds.Top + 1);
g.DrawLine(dark, bounds.Left, bounds.Top, bounds.Width - 2, bounds.Top);
// right
g.DrawLine(light, bounds.Width - 1, bounds.Top, bounds.Width - 1, bounds.Height - 1);
g.DrawLine(dark, bounds.Width - 2, bounds.Top, bounds.Width - 2, bounds.Height - 2);
}
finally {
if (light != null) {
light.Dispose();
}
if (dark != null) {
dark.Dispose();
}
}
}
/// <summary>
/// Draws an un-themed GroupBox with a text label.
/// Variation of the logic in GroupBox.DrawGroupBox().
/// </summary>
/// <internalonly/>
private static void DrawUnthemedGroupBoxWithText(Graphics g, Rectangle bounds, string groupBoxText, Font font, Color textColor, TextFormatFlags flags, GroupBoxState state) {
// Calculate text area, and render text inside it
Rectangle textBounds = bounds;
textBounds.Width -= textOffset;
Size measuredBounds = TextRenderer.MeasureText(g, groupBoxText, font, new Size(textBounds.Width, textBounds.Height), flags);
textBounds.Width = measuredBounds.Width;
textBounds.Height = measuredBounds.Height;
if ((flags & TextFormatFlags.Right) == TextFormatFlags.Right) {
textBounds.X = bounds.Right - textBounds.Width - textOffset;
}
else {
textBounds.X += textOffset;
}
TextRenderer.DrawText(g, groupBoxText, font, textBounds, textColor, flags);
// Pad text area to stop background from touching text
if (textBounds.Width > 0)
textBounds.Inflate(2, 0);
Pen light = new Pen(SystemColors.ControlLight);
Pen dark = new Pen(SystemColors.ControlDark);
int boxTop = bounds.Top + font.Height / 2;
// left
g.DrawLine(light, bounds.Left + 1, boxTop, bounds.Left + 1, bounds.Height - 1);
g.DrawLine(dark, bounds.Left, boxTop - 1, bounds.Left, bounds.Height - 2);
// bottom
g.DrawLine(light, bounds.Left, bounds.Height - 1, bounds.Width, bounds.Height - 1);
g.DrawLine(dark, bounds.Left, bounds.Height - 2, bounds.Width - 1, bounds.Height - 2);
// top-left
g.DrawLine(light, bounds.Left + 1, boxTop, textBounds.X - 2, boxTop);
g.DrawLine(dark, bounds.Left, boxTop - 1, textBounds.X - 3, boxTop - 1);
// top-right
g.DrawLine(light, textBounds.X + textBounds.Width + 1, boxTop, bounds.Width - 1, boxTop);
g.DrawLine(dark, textBounds.X + textBounds.Width + 2, boxTop - 1, bounds.Width - 2, boxTop - 1);
// right
g.DrawLine(light, bounds.Width - 1, boxTop, bounds.Width - 1, bounds.Height - 1);
g.DrawLine(dark, bounds.Width - 2, boxTop - 1, bounds.Width - 2, bounds.Height - 2);
light.Dispose();
dark.Dispose();
}
private static Color DefaultTextColor(GroupBoxState state) {
if (RenderWithVisualStyles) {
InitializeRenderer((int)state);
return visualStyleRenderer.GetColor(ColorProperty.TextColor);
}
else {
return SystemColors.ControlText;
}
}
private static void InitializeRenderer(int state) {
int part = GroupBoxElement.Part;
if (AccessibilityImprovements.Level2
&& SystemInformation.HighContrast
&& ((GroupBoxState)state == GroupBoxState.Disabled)
&& VisualStyleRenderer.IsCombinationDefined(GroupBoxElement.ClassName, VisualStyleElement.Button.GroupBox.HighContrastDisabledPart)) {
part = VisualStyleElement.Button.GroupBox.HighContrastDisabledPart;
}
if (visualStyleRenderer == null) {
visualStyleRenderer = new VisualStyleRenderer(GroupBoxElement.ClassName, part, state);
}
else {
visualStyleRenderer.SetParameters(GroupBoxElement.ClassName, part, state);
}
}
}
}
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