Motif Label Size: Keep It Consistent On Text Change

Hey guys! Ever wrestled with Motif label sizes? It's a common head-scratcher, especially when you're dynamically updating the text using XtVaSetValues. You set everything up perfectly – initial text, position, size – and then BAM! The label size goes haywire when the text changes. Let's dive deep into this issue and figure out how to keep your Motif labels playing nice.

Understanding the Motif Label Size Conundrum

So, you've got your Motif application humming along, complete with a snazzy xmPushButtonWidgetClass button and an elegant xmLabelWidgetClass label. You've meticulously crafted the initial text, carefully positioned the label, and painstakingly set the size. Everything looks perfect... until you change the label's text using XtVaSetValues. Then, chaos ensues! The label size stretches, shrinks, or does something entirely unexpected. What gives? — Mariners Vs. Mets: MLB Showdown Guide

The core of the issue lies in how Motif handles label resizing. By default, Motif labels are designed to be dynamic. This means they automatically adjust their size to fit the text they contain. While this is super convenient in many cases, it can be a real pain when you want to maintain a consistent label size regardless of the text. You might be thinking, "Okay, I'll just set the width and height and be done with it!" But it's not always that simple. Motif's layout management can sometimes override your explicit size settings, especially when the text changes.

Think of it like this: Motif is trying to be helpful by making sure your labels always display their content fully. But sometimes, you need to be the boss and tell Motif, "Hey, I've got this! Keep the label this size, no matter what!" That's where the tricks and techniques we'll explore come in handy.

To really grasp this, let's break down the key factors at play:

• XmNlabelString: This resource holds the text displayed in the label. Changing this is the trigger for the resizing shenanigans.
• XmNwidth and XmNheight: These resources seem like the obvious solution, but they can be overridden by Motif's layout management.
• XmNrecomputeSize: This resource, when set to False, should prevent the label from automatically resizing. However, it doesn't always work as expected on its own.
• Parent Widget's Layout Management: The parent widget (e.g., a XmRowColumn or XmForm) also plays a role. Its layout rules can influence the label's size.

So, how do we tame this beast? Let's explore some tried-and-true solutions.

Taming the Motif Label: Strategies for Consistent Size

Alright, let's get our hands dirty and explore some practical strategies to keep your Motif label sizes consistent, even when the text changes. We'll cover several techniques, from the straightforward to the slightly more involved, so you can choose the best approach for your specific situation. — Days Until April 28th: Your Ultimate Countdown Guide

1. The XmNrecomputeSize Trick (with a Caveat)

As we mentioned earlier, the XmNrecomputeSize resource seems like the obvious solution. Setting it to False should, in theory, prevent the label from automatically resizing. You might try something like this:

XtVaSetValues(label, XmNrecomputeSize, False, NULL);

However, you might find that this alone isn't enough. Motif's layout management can sometimes be stubborn, especially if the parent widget has strong opinions about sizing. So, while this is a good first step, it often needs to be combined with other techniques.

2. Explicitly Setting Width and Height

The next logical step is to explicitly set the XmNwidth and XmNheight resources. This tells Motif, "Hey, I know what size I want!" For example:

XtVaSetValues(label,
    XmNwidth, 100,
    XmNheight, 30,
    NULL);

This works well in many cases, especially if you have a simple layout. However, if your label is inside a complex layout managed by a XmRowColumn or XmForm, the parent widget might still try to resize the label. This is where things get a bit more interesting.

3. The Parent Widget's Influence: XmNadjustLast and Friends

If your label is stubbornly refusing to stay the size you want, it's time to consider the parent widget's layout management. Widgets like XmRowColumn and XmForm have resources that control how they size and position their children. — Mariners Vs. Blue Jays: Where To Watch

For XmRowColumn widgets, the XmNadjustLast resource can be a culprit. If it's set to True (the default), the XmRowColumn might stretch the last child (which could be your label) to fill the available space. Try setting it to False:

XtVaSetValues(rowColumn,
    XmNadjustLast, False,
    NULL);

For XmForm widgets, the XmNtopAttachment, XmNbottomAttachment, XmNleftAttachment, and XmNrightAttachment resources determine how a child widget is positioned and sized relative to the form's edges or other widgets. If these attachments are set in a way that allows the label to stretch, it will. You might need to adjust these attachments to create a more rigid size constraint.

4. The XmStringExtent Technique: Measuring Text Before Setting

This is a more advanced technique, but it gives you fine-grained control over the label's size. The idea is to measure the text before you set it in the label, and then set the label's size based on the measured text dimensions.

Here's the general approach:

1. Create an XmFontList (if you don't already have one).
2. Create an XmString from the text you want to display.
3. Call XmStringExtent() to get the width and height of the XmString.
4. Set the XmNwidth and XmNheight of the label based on the measured dimensions.
5. Set the XmNlabelString of the label.

Here's a code snippet to illustrate:

XmString labelString = XmStringCreateLocalized(