greenshot/Greenshot/Helpers/ScaleHelper.cs

339 lines
15 KiB
C#

/*
* Greenshot - a free and open source screenshot tool
* Copyright (C) 2007-2021 Thomas Braun, Jens Klingen, Robin Krom
*
* For more information see: http://getgreenshot.org/
* The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
using System;
using System.Drawing;
using System.Windows.Forms;
using Greenshot.Drawing;
namespace Greenshot.Helpers {
/// <summary>
/// Offers a few helper functions for scaling/aligning an element with another element
/// </summary>
public static class ScaleHelper {
[Flags]
public enum ScaleOptions {
/// <summary>
/// Default scale behavior.
/// </summary>
Default = 0x00,
/// <summary>
/// Scale a rectangle in two our four directions, mirrored at it's center coordinates
/// </summary>
Centered = 0x01,
/// <summary>
/// Scale a rectangle maintaining it's aspect ratio
/// </summary>
Rational = 0x02
}
/// <summary>
/// calculates the Size an element must be resized to, in order to fit another element, keeping aspect ratio
/// </summary>
/// <param name="currentSize">the size of the element to be resized</param>
/// <param name="targetSize">the target size of the element</param>
/// <param name="crop">in case the aspect ratio of currentSize and targetSize differs: shall the scaled size fit into targetSize (i.e. that one of its dimensions is smaller - false) or vice versa (true)</param>
/// <returns>a new SizeF object indicating the width and height the element should be scaled to</returns>
public static SizeF GetScaledSize(SizeF currentSize, SizeF targetSize, bool crop) {
float wFactor = targetSize.Width/currentSize.Width;
float hFactor = targetSize.Height/currentSize.Height;
float factor = crop ? Math.Max(wFactor, hFactor) : Math.Min(wFactor, hFactor);
return new SizeF(currentSize.Width * factor, currentSize.Height * factor);
}
/// <summary>
/// calculates the position of an element depending on the desired alignment within a RectangleF
/// </summary>
/// <param name="currentRect">the bounds of the element to be aligned</param>
/// <param name="targetRect">the rectangle reference for alignment of the element</param>
/// <param name="alignment">the System.Drawing.ContentAlignment value indicating how the element is to be aligned should the width or height differ from targetSize</param>
/// <returns>a new RectangleF object with Location aligned aligned to targetRect</returns>
public static RectangleF GetAlignedRectangle(RectangleF currentRect, RectangleF targetRect, ContentAlignment alignment) {
RectangleF newRect = new RectangleF(targetRect.Location, currentRect.Size);
switch(alignment) {
case ContentAlignment.TopCenter:
newRect.X = (targetRect.Width - currentRect.Width) / 2;
break;
case ContentAlignment.TopRight:
newRect.X = targetRect.Width - currentRect.Width;
break;
case ContentAlignment.MiddleLeft:
newRect.Y = (targetRect.Height - currentRect.Height) / 2;
break;
case ContentAlignment.MiddleCenter:
newRect.Y = (targetRect.Height - currentRect.Height) / 2;
newRect.X = (targetRect.Width - currentRect.Width) / 2;
break;
case ContentAlignment.MiddleRight:
newRect.Y = (targetRect.Height - currentRect.Height) / 2;
newRect.X = targetRect.Width - currentRect.Width;
break;
case ContentAlignment.BottomLeft:
newRect.Y = targetRect.Height - currentRect.Height;
break;
case ContentAlignment.BottomCenter:
newRect.Y = targetRect.Height - currentRect.Height;
newRect.X = (targetRect.Width - currentRect.Width) / 2;
break;
case ContentAlignment.BottomRight:
newRect.Y = targetRect.Height - currentRect.Height;
newRect.X = targetRect.Width - currentRect.Width;
break;
}
return newRect;
}
/// <summary>
/// Calculates target size of a given rectangle scaled by dragging one of its handles (corners)
/// </summary>
/// <param name="originalRectangle">bounds of the current rectangle, scaled values will be written to this reference</param>
/// <param name="resizeHandlePosition">position of the handle/gripper being used for resized, see constants in Gripper.cs, e.g. Gripper.POSITION_TOP_LEFT</param>
/// <param name="resizeHandleCoords">coordinates of the used handle/gripper</param>
/// <param name="options">ScaleOptions to use when scaling</param>
public static void Scale(ref RectangleF originalRectangle, Positions resizeHandlePosition, PointF resizeHandleCoords, ScaleOptions? options) {
options ??= GetScaleOptions();
if ((options & ScaleOptions.Rational) == ScaleOptions.Rational) {
AdjustCoordsForRationalScale(originalRectangle, resizeHandlePosition, ref resizeHandleCoords);
}
if ((options & ScaleOptions.Centered) == ScaleOptions.Centered) {
// store center coordinates of rectangle
float rectCenterX = originalRectangle.Left + originalRectangle.Width / 2;
float rectCenterY = originalRectangle.Top + originalRectangle.Height / 2;
// scale rectangle using handle coordinates
Scale(ref originalRectangle, resizeHandlePosition, resizeHandleCoords);
// mirror handle coordinates via rectangle center coordinates
resizeHandleCoords.X -= 2 * (resizeHandleCoords.X - rectCenterX);
resizeHandleCoords.Y -= 2 * (resizeHandleCoords.Y - rectCenterY);
// scale again with opposing handle and mirrored coordinates
resizeHandlePosition = (Positions)((((int)resizeHandlePosition) + 4) % 8);
Scale(ref originalRectangle, resizeHandlePosition, resizeHandleCoords);
} else {
Scale(ref originalRectangle, resizeHandlePosition, resizeHandleCoords);
}
}
/// <summary>
/// Calculates target size of a given rectangle scaled by dragging one of its handles (corners)
/// </summary>
/// <param name="originalRectangle">bounds of the current rectangle, scaled values will be written to this reference</param>
/// <param name="resizeHandlePosition">position of the handle/gripper being used for resized, see constants in Gripper.cs, e.g. Gripper.POSITION_TOP_LEFT</param>
/// <param name="resizeHandleCoords">coordinates of the used handle/gripper</param>
private static void Scale(ref RectangleF originalRectangle, Positions resizeHandlePosition, PointF resizeHandleCoords) {
switch(resizeHandlePosition) {
case Positions.TopLeft:
originalRectangle.Width = originalRectangle.Left + originalRectangle.Width - resizeHandleCoords.X;
originalRectangle.Height = originalRectangle.Top + originalRectangle.Height - resizeHandleCoords.Y;
originalRectangle.X = resizeHandleCoords.X;
originalRectangle.Y = resizeHandleCoords.Y;
break;
case Positions.TopCenter:
originalRectangle.Height = originalRectangle.Top + originalRectangle.Height - resizeHandleCoords.Y;
originalRectangle.Y = resizeHandleCoords.Y;
break;
case Positions.TopRight:
originalRectangle.Width = resizeHandleCoords.X - originalRectangle.Left;
originalRectangle.Height = originalRectangle.Top + originalRectangle.Height - resizeHandleCoords.Y;
originalRectangle.Y = resizeHandleCoords.Y;
break;
case Positions.MiddleLeft:
originalRectangle.Width = originalRectangle.Left + originalRectangle.Width - resizeHandleCoords.X;
originalRectangle.X = resizeHandleCoords.X;
break;
case Positions.MiddleRight:
originalRectangle.Width = resizeHandleCoords.X - originalRectangle.Left;
break;
case Positions.BottomLeft:
originalRectangle.Width = originalRectangle.Left + originalRectangle.Width - resizeHandleCoords.X;
originalRectangle.Height = resizeHandleCoords.Y - originalRectangle.Top;
originalRectangle.X = resizeHandleCoords.X;
break;
case Positions.BottomCenter:
originalRectangle.Height = resizeHandleCoords.Y - originalRectangle.Top;
break;
case Positions.BottomRight:
originalRectangle.Width = resizeHandleCoords.X - originalRectangle.Left;
originalRectangle.Height = resizeHandleCoords.Y - originalRectangle.Top;
break;
default:
throw new ArgumentException("Position cannot be handled: "+resizeHandlePosition);
}
}
/// <summary>
/// Adjusts resizeHandleCoords so that aspect ratio is kept after resizing a given rectangle with provided arguments.
/// An adjustment can always be done in two ways, e.g. *in*crease width until fit or *de*crease height until fit.
/// To avoid objects growing near infinity unexpectedly in certain combinations, the adjustment will choose the
/// option resulting in the smaller rectangle.
/// </summary>
/// <param name="originalRectangle">bounds of the current rectangle</param>
/// <param name="resizeHandlePosition">position of the handle/gripper being used for resized, see Position</param>
/// <param name="resizeHandleCoords">coordinates of the used handle/gripper, adjusted coordinates will be written to this reference</param>
private static void AdjustCoordsForRationalScale(RectangleF originalRectangle, Positions resizeHandlePosition, ref PointF resizeHandleCoords) {
SizeF selectedRectangle, newSize;
switch(resizeHandlePosition) {
case Positions.TopLeft:
selectedRectangle = new SizeF(originalRectangle.Right - resizeHandleCoords.X, originalRectangle.Bottom - resizeHandleCoords.Y);
newSize = GetNewSizeForRationalScale(originalRectangle.Size, selectedRectangle);
resizeHandleCoords.X = originalRectangle.Right - newSize.Width;
resizeHandleCoords.Y = originalRectangle.Bottom - newSize.Height;
break;
case Positions.TopRight:
selectedRectangle = new SizeF(resizeHandleCoords.X - originalRectangle.Left, originalRectangle.Bottom - resizeHandleCoords.Y);
newSize = GetNewSizeForRationalScale(originalRectangle.Size, selectedRectangle);
resizeHandleCoords.X = originalRectangle.Left + newSize.Width;
resizeHandleCoords.Y = originalRectangle.Bottom - newSize.Height;
break;
case Positions.BottomLeft:
selectedRectangle = new SizeF(originalRectangle.Right - resizeHandleCoords.X, resizeHandleCoords.Y - originalRectangle.Top);
newSize = GetNewSizeForRationalScale(originalRectangle.Size, selectedRectangle);
resizeHandleCoords.X = originalRectangle.Right - newSize.Width;
resizeHandleCoords.Y = originalRectangle.Top + newSize.Height;
break;
case Positions.BottomRight:
selectedRectangle = new SizeF(resizeHandleCoords.X - originalRectangle.Left, resizeHandleCoords.Y - originalRectangle.Top);
newSize = GetNewSizeForRationalScale(originalRectangle.Size, selectedRectangle);
resizeHandleCoords.X = originalRectangle.Left + newSize.Width;
resizeHandleCoords.Y = originalRectangle.Top + newSize.Height;
break;
}
}
/// <summary>
/// For an original size, and a selected size, returns the the largest possible size that
/// * has the same aspect ratio as the original
/// * fits into selected size
/// </summary>
/// <param name="originalSize">size to be considered for keeping aspect ratio</param>
/// <param name="selectedSize">selection size (i.e. the size we'd produce if we wouldn't keep aspect ratio)</param>
/// <returns></returns>
private static SizeF GetNewSizeForRationalScale(SizeF originalSize, SizeF selectedSize)
{
SizeF newSize = selectedSize;
float originalRatio = originalSize.Width / originalSize.Height;
float selectedRatio = selectedSize.Width / selectedSize.Height;
// will fix orientation if the scaling causes size to be flipped in any direction
int flippedRatioSign = Math.Sign(selectedRatio) * Math.Sign(originalRatio);
if (Math.Abs(selectedRatio) > Math.Abs(originalRatio))
{
// scaled rectangle (ratio) would be wider than original
// keep height and tweak width to maintain aspect ratio
newSize.Width = selectedSize.Height * originalRatio * flippedRatioSign;
}
else if (Math.Abs(selectedRatio) < Math.Abs(originalRatio))
{
// scaled rectangle (ratio) would be taller than original
// keep width and tweak height to maintain aspect ratio
newSize.Height = selectedSize.Width / originalRatio * flippedRatioSign;
}
return newSize;
}
public static void Scale(Rectangle boundsBeforeResize, int cursorX, int cursorY, ref RectangleF boundsAfterResize) {
Scale(boundsBeforeResize, cursorX, cursorY, ref boundsAfterResize, null);
}
public static void Scale(Rectangle boundsBeforeResize, int cursorX, int cursorY, ref RectangleF boundsAfterResize, IDoubleProcessor angleRoundBehavior) {
Scale(boundsBeforeResize, Positions.TopLeft, cursorX, cursorY, ref boundsAfterResize, angleRoundBehavior);
}
public static void Scale(Rectangle boundsBeforeResize, Positions gripperPosition, int cursorX, int cursorY, ref RectangleF boundsAfterResize, IDoubleProcessor angleRoundBehavior) {
ScaleOptions opts = GetScaleOptions();
bool rationalScale = (opts & ScaleOptions.Rational) == ScaleOptions.Rational;
bool centeredScale = (opts & ScaleOptions.Centered) == ScaleOptions.Centered;
if(rationalScale) {
double angle = GeometryHelper.Angle2D(boundsBeforeResize.X, boundsBeforeResize.Y, cursorX, cursorY);
if(angleRoundBehavior != null) {
angle = angleRoundBehavior.Process(angle);
}
int dist = GeometryHelper.Distance2D(boundsBeforeResize.X, boundsBeforeResize.Y, cursorX, cursorY);
boundsAfterResize.Width = (int)Math.Round(dist * Math.Cos(angle / 180 * Math.PI));
boundsAfterResize.Height = (int)Math.Round(dist * Math.Sin(angle / 180 * Math.PI));
}
if(centeredScale) {
float wdiff = boundsAfterResize.Width - boundsBeforeResize.Width;
float hdiff = boundsAfterResize.Height - boundsBeforeResize.Height;
boundsAfterResize.Width += wdiff;
boundsAfterResize.Height += hdiff;
boundsAfterResize.X -= wdiff;
boundsAfterResize.Y -= hdiff;
}
}
/// <returns>the current ScaleOptions depending on modifier keys held down</returns>
public static ScaleOptions GetScaleOptions() {
bool anchorAtCenter = (Control.ModifierKeys & Keys.Control) != 0;
bool maintainAspectRatio = (Control.ModifierKeys & Keys.Shift) != 0;
ScaleOptions opts = ScaleOptions.Default;
if(anchorAtCenter) opts |= ScaleOptions.Centered;
if(maintainAspectRatio) opts |= ScaleOptions.Rational;
return opts;
}
public interface IDoubleProcessor {
double Process(double d);
}
public class ShapeAngleRoundBehavior : IDoubleProcessor {
public static ShapeAngleRoundBehavior Instance = new();
private ShapeAngleRoundBehavior() {}
public double Process(double angle) {
return Math.Round((angle+45)/90)*90 - 45;
}
}
public class LineAngleRoundBehavior : IDoubleProcessor {
public static LineAngleRoundBehavior Instance = new();
private LineAngleRoundBehavior() {}
public double Process(double angle) {
return Math.Round(angle/15)*15;
}
}
}
}