Ricci Adams
Pixel Winch Quick Guide

Table of Contents


When you first launch Pixel Winch, it places an icon in menu bar. Click this icon and select “Capture Selection…” to capture your first screenshot:

The Pixel Winch window will appear. It's divided into five sections:

Toolbar Scale Mode Rulers Canvas History
  • Toolbar - Select a tool to navigate around the current screenshot, or place measurements on it.
  • Scale Mode - Select either 1x, 2x, or 3x scale mode to adjust measurements for Retina displays.
  • Rulers - Click and drag a ruler to place a guide on the screenshot.
  • Canvas - Displays the current screenshot.
  • History - Select a previous screenshot to load it into the canvas.

Scale Mode

By default, Pixel Winch will display all measurements in device pixels. When working with screenshots from a retina display, you may prefer measurements to be in logical points instead.

You can change the scale mode via the buttons in the top-right of the window:

You can also use 1, 2, or 3 on the keyboard.


Guides offer a fast way to check the alignment of two objects. To place a guide, click on either the horizontal or vertical ruler and drag out onto the canvas. To remove a guide, drag it off the canvas.

Use guides to quickly check alignment.

Grapple Tool

The Grapple Tool quickly measures areas of solid color or gradients. Select the tool by clicking in the toolbar or by pressing G on the keyboard.

As you move your mouse over the canvas, Pixel Winch measures lines of contiguous pixels with the solid color. Starting at the pixel under the mouse cursor, a line extends either horizontally or vertically until a different color occurs:

Click to convert the temporary preview line into a placed grapple. By default, the Grapple Tool measures along the vertical axis. You can switch to the horizontal axis by pressing Shift G. You can also hold down Option to temporarily select the opposite axis.

While the Grapple Tool's preview mode is limited to solid colors, placed grapples can measure gradients. To do so, hold down the mouse button and drag up or down during the placement process. The grapple will “power up” and blast through the gradient:

Grapples normally stop at guides. This is useful when measuring a label's baseline to another element. Place a guide at the baseline, then use grapples to measure from the guide to the element:

Combine grapples with guides to easily measure text metrics.

This usage is so common, it warranted a shortcut: hold down Command while using the Grapple Tool to place guides.

To bypass guides and rectangles during grapple placement, hold down Shift.

Line Tool

Some situations require more precision than the Grapple Tool provides. No worries — select the Line Tool by clicking in the toolbar or by pressing L on the keyboard. Click on the canvas and drag to draw a horizontal or vertical line.

Rectangle Tool

The Rectangle Tool draws rectangles on the canvas. Select it by clicking in the toolbar or by pressing R on the keyboard.

Like guides, rectangles block grapples. This allows you to easily measure the bounding boxes of complex shapes:

Use rectangles to measure the bounding box of a complex shape.

When drawing a rectangle, hold down Shift to constrain the shape to a square. You can move the rectangle by holding down Space.

Hand Tool and Zoom Tool

Pixel Winch implements the familiar Hand Tool and Zoom Tool found in most design applications.

Activate the Hand Tool by pressing H. Click and drag the canvas to move around.

Activate the Zoom Tool by pressing Z. Click on the canvas to zoom in. Hold down Option and click to zoom out.

Marquee Tool

The Marquee Tool selects a portion of the screenshot. Activate it using M and then drag on the canvas. Use Command C to copy the selection to the clipboard.

Move Tool

Grapples, lines, and rectangles may be modified after placement. For example, you may wish to enlarge a rectangle after placement:

First, select the Move Tool by pressing V. Click on the rectangle — the measurement label will become dark blue and resize knobs will appear. Drag one of the knobs to resize the rectangle to the desired size:

Select an object and drag a knob to resize it.

Keyboard Selection

When an object is selected, the Arrows move it by a single pixel in the specified direction. Use ShiftArrows to move it by 10 pixels.

You can also manipulate a single edge or corner using the keyboard. First, double click on the resize knob or use Option Arrows to enter knob selection mode. Once the knob is selected, you may move it just like an object:

Resize an object via edge selection.

Shortcut Chart and Legend


VActivate Move Tool
HActivate Hand Tool
MActivate Marquee Tool
RActivate Rectangle Tool
LActivate Line Tool
GActivate Grapple Tool
ZActivate Zoom Tool
1Select 1x scale mode.
2Select 2x scale mode.
3Select 3x scale mode.
Command NImport image file from clipboard
Command DDuplicate selected object
Command SExport canvas as an image file
Command DeleteDelete current screenshot
Command 1 - 8Zoom to 100% - 800%
Command +Zoom in
Command −Zoom out
Command {Load previous screenshot in history
Command }Load next screenshot in history
Command ;Toggle visibility of guides
ArrowsMove selection by 1 pixel
Shift ArrowsMove selection by 10 pixels
Option ArrowsSelect edge/corner of selected object
Space Shortcuts
SpaceHand Tool
Space CommandZoom In
Space OptionZoom Out
Modifier Keys
Move ToolOptionDuplicate a dragged object.
Marquee ToolShiftConstrain marquee to a square.
Rectangle ToolShiftUse during placement to constrain shape to a square.
Rectangle ToolSpaceUse during placement to move the drawn shape.
Grapple ToolOptionTemporarily select the alternate axis.
Grapple ToolCommandTemporarily enter guide placement mode.
Grapple ToolShiftUse during placement to bypass guides and rectangles.
Zoom ToolOptionTemporarily select the inverse zooming direction.