Drag the four corner handles to enclose the printed grid on a single chart page. The corners you set here become the anchor for every other measurement Markup R-XP makes on this page.

On this page

 

 

What this step is for

 

You will arrive at this step in one of two ways: by tapping a page on the Review Grids screen that needs a fix, or because Markup R-XP could not detect a grid automatically on this page when the project was created.

Whichever way you got here, the job is the same: tell Markup R-XP exactly where the four corners of the printed grid sit on the page. Get those four corners right and the rest of the adjust-grid steps (size, straightening) will line up naturally.

 

The wizard begins with the corners drawn where it thinks they should be. On a clean page that is often spot-on - you only need to confirm and tap Next. On more difficult pages (faint print, scanned PDFs, decorative borders) the auto-detection can land in the wrong place and you will need to drag each handle into position.

The screen at a glance

 

The Set Corners screen shows one chart page filling the white panel with four draggable corner handles around the printed grid. An instruction strip sits along the top and a floating chip is on the left edge.
Figure 1. The Set Corners screen. (1) A short instruction strip along the top reminds you of the task. (2) The top-left corner handle. (3) Top-right. (4) Bottom-left. (5) Bottom-right. (6) The floating chip toggles between free-form and bounding-box corners. (7) The Back button returns to the chart overview. (8) The Next button moves on to the next step.

Placing the corners

 

Each corner is a small handle you can drag with your finger. As you drag, a magnifier circle appears so you can land the handle precisely on the corner of the printed grid.

  1. Pinch to zoom in on a corner. Working at a comfortable size makes it much easier to land the handle accurately.
  2. Touch and hold a corner handle. The magnifier pops up above your finger showing the area under the handle, crosshair included.
  3. Drag the handle onto the printed corner. Watch the magnifier - you want the crosshair to sit on the very corner of the printed grid line.
  4. Release. The handle stays put.
  5. Repeat for the other three corners. Work all the way round until every corner sits cleanly on the grid.
A finger dragging a corner handle, with a circular magnifier showing the area beneath the finger and a crosshair indicating the exact position.
Figure 2. The magnifier appears above your finger while you drag. (1) Your finger holds the handle. (2) The magnifier shows the area under the finger. (3) The crosshair pinpoints where the handle will land when you let go.

Tip. You do not have to be perfectly accurate on the very first pass. Place each corner roughly, then zoom in further and nudge them precisely. Two passes are often quicker than one slow careful one.

Free-form versus bounding-box corners

 

The floating chip on the left edge has a single toggle button that switches between two ways of drawing the corners.

Two views of the floating chip: on the left, an irregular trapezoid icon indicating free-form corners; on the right, a square icon indicating bounding-box corners.
Figure 3. The corner-type toggle. (1) Free-form lets every corner be in any position - the four corners can form any quadrilateral. (2) Bounding-box constrains the corners to a true rectangle - move one corner and the others adjust to stay square.

Free-form corners (the default)

Each corner moves independently. Use this on pages where the print is slightly skewed or distorted, so you can match the actual shape of the printed grid even if it is not a perfect rectangle.

Bounding-box corners

The four corners are locked into a rectangle. Drag one corner and the opposite sides snap to keep the shape square. Use this on cleanly-printed pages where you just want a tidy outline.

Note. If you switch modes, a brief toast confirms the change: “Switched to bounding-box corner points” or “Switched to raw points”. You can flip back and forth without losing your edits.

Cycling through detected outlines

 

On some pages, Markup R-XP detects more than one possible grid outline - perhaps it found a decorative border as well as the actual grid, or the grid contains a sub-region that looks like its own outline. When that happens, a small “Outline 1 of N” button appears in the bottom-right corner next to Next.

A chart page with the Outline 1 of 3 button visible in the bottom-right corner next to the Next button. The current outline is highlighted on the page.
Figure 4. When the page has more than one candidate outline. (1) The currently-selected outline is drawn on the page. (2) The Outline N of M button cycles through the candidates - the corners reposition each time you tap it.
  1. Tap the Outline button. The next candidate outline becomes active.
  2. Check the corners on the page. If the new candidate sits more accurately on the printed grid, leave it selected.
  3. Keep tapping to cycle through. When you reach the end the count wraps back to one.
  4. Pick the candidate that is closest to the actual grid, then drag any remaining corners into place. A near-fit candidate followed by a small drag is faster than dragging all four corners from scratch.

Moving on

 

When all four corners sit cleanly on the printed grid, tap Next in the bottom-right corner. Markup R-XP straightens the chart against your new corners if necessary, then takes you to the next step in the adjust-grid loop: Confirm Size.

Heads up. If your corners are arranged in an impossible shape (for example, two corners on top of each other) the wizard will refuse to move on and show a toast describing the problem. Rearrange the corners and try Next again.

If you want to back out, tap Back to return to the Review Grids screen with no changes saved.

Tips and common questions

Here are answers to the most common questions about setting corners.

Q: The corner handles look right but I cannot drag them. What is wrong?

Answer: You may be zoomed out too far for the touch target.

Pinch in to zoom up on a corner before trying to drag it. The handles are easier to grab when they are large on screen, and the magnifier gives you much better placement accuracy too.

Q: The auto-detected corners are completely off the page. Is the page broken?

Answer: No - the detection failed but you can still set the corners by hand.

Drag each corner one at a time onto the four corners of the printed grid. You may also find that cycling through the candidate outlines (when the “Outline N of M” button is visible) gives you a better starting point.

Q: My chart looks straight but the corners want to be at an angle. Should I use free-form or bounding-box?

Answer: Use free-form first.

Drag each corner to its own printed position, even if the resulting shape is slightly skewed. The next step (straightening) corrects the skew while keeping the grid lined up. If you force bounding-box on a skewed page, you will lose grid alignment along one or two edges.

Q: I tapped the Outline button by accident and want my original outline back.

Answer: Keep tapping the Outline button until you cycle back to the candidate you started on.

The count wraps - if there are three outlines you will return to outline one after two more taps.

Q: Can I undo a corner move?

Answer: Not on this step.

If you drag a corner to the wrong place, just drag it back to the right place. The undo / redo controls live on the later Straighten Chart step.

What's next?

 

After setting the corners, the next step is to confirm the size of the grid in cells - how many rows tall and how many columns wide it is.

Markup R-XP will use the corners you set here as the boundary for that count. Once the size is confirmed you will move on to the final corner-editing step, Straighten Chart, before returning to the chart overview.