[Bug] BarChart does not respect yAxis.min when all data is below min (and max is undefined)

[tmtron]

Version

5.4.3

Link to Minimal Reproduction

https://echarts.apache.org/examples/en/editor.html?code=PYBwLglsB2AEC8sDeAoWsAeBBDEDOAXMmurGAJ4gCmRA5AMYCGYVA5sAE7m0A0J6AE2aMiAbVpZaAXRIBfPunI58RVKTKUasWgDdGAGwCuVXv1gBbCNCIBWOQth4qHCFUKxRZtethCwIjwBaAEYABlCpB3UKajoAI0YOWjNZEhlZAG4gA

Steps to Reproduce

• yAxis.min=5
• we have only 1 bar with value -100

Current Behavior

The bar-chart ignores the yAxis.min setting (5) and instead seems to use the auto-calculated value (100)

Expected Behavior

• The yAxis minimum value should be 5, as specified

Environment

- OS: Windows 11
- Browser: Google Chrome
- Framework: none

Any additional comments?

it works as expected when

• we set an explicit max: e.g. 6: Example
• we use -5 as yAxis.min, Example
• when we have some data that is higher than yAxis.min: example

[helgasoft]

A very thorough analysis and bug confirmed.
OTOH, what would be the use of such chart ?

option = {
  xAxis: { data: ['A'] },  yAxis: { min: 5 },
  series: [ { data: [-100], type: 'bar' }]
};

[tmtron]

Our use-case is that customers can create custom dashboards and add many charts side-by-side or below each other.
In this case they have 3 bar-charts side-by-side and want to compare data from 3 different devices. All devices have 3 channels 'A', 'B', 'C' which are expected to return data that is higher than a certain offset: e.g. 220.
In this case it makes sense to set the yAxis.min to 220 so that you can see small differences exactly, e.g. when the data are: 220, 225, 223. And of course, you want to set the same min to all 3 charts, so that you can easily compare them.
When a channel has an error, it will return a negative number: e.g. -1, -2, etc.

And now we have this special case, where all 3 channels return an error and in this case, the yAxis scale is different:

The biggest issue with that is that the customers will check the config of chart 2 and see that they have set the min correctly, but the chart is not okay. This causes confustion and a lot of wasted support time on our side.

BTW: I just noticed that the label of bar B in the 3rd chart is missing: I created a separate issue for that: #19196

[echarts-bot]

This issue is labeled with difficulty: easy.
@tmtron Would you like to debug it by yourself? This is a quicker way to get your problem fixed. Or you may wait for the community to fix.

Please have a look at How to debug ECharts if you'd like to give a try. 🤓

[helgasoft]

Much better, @tmtron, a complete description of the problem. Now it becomes evident that it's a design issue.
Values between 0 and 220 are irrelevant, thus the threshold(220 ) has to be substracted from data values. Then yAxis needs to be re-labeled ... et voila.
Demo Code

[tmtron]

@helgasoft Your proposal is for sure nice, but just a workaround for the bug.
And you must also consider that we don't just create a fixed chart for one customer, so we would need to change the config dialouge to let the customer define if they want that "error" display or not.
We definitely don't want to add complexity to our input dialogs or source code just to make up for bugs in the chart library.

BTW: an easier workaround would be to simply check if all data are below 0 and then set max to the threshold plus some constant, e.g. 220+10 = 230: Example

[soniyaprasad77]

@tmtron
Here's a revised code snippet implementing the dynamic adjustment of yAxis.max based on whether all data points are below zero:

const data = [-1, -2, -3]; // Example data
const threshold = 220;

// Check if all data points are below zero
const allBelowZero = data.every(value => value < 0);

// Dynamically set yAxis.max based on the condition
const maxY = allBelowZero ? threshold + 10 : null;

const option = {
xAxis: {
type: 'category',
data: ['A', 'B', 'C'] // Example categories
},
yAxis: {
type: 'value',
min: threshold,
max: maxY // Set to threshold + 10 if all data points are below zero
},
series: [
{
data: data,
type: 'bar'
}
]
};

This adjustment allows for a more dynamic setting of the yAxis.max based on the data provided, ensuring the chart accommodates the range while avoiding hard-coded values. It keeps the configuration adaptable and avoids unnecessary complexity in the input dialogs or source code.

[mertokten]

@tmtron
I have added this code snippet after line 235 in the scaleRawExtentInfo.ts file and it seemed to fix the current bug. However I am not sure whether it breaks something when maxFixed and minFixed are set like this.

    if (!maxFixed && minFixed) {
        if (min > max) {
            max = min + 10;
            maxFixed = true;
        }
    } else if (!minFixed && maxFixed) {
        if (max < min) {
            min = max - 10;
            minFixed = true;
        }
    }

I am currently testing if it breaks anything else by checking with the other test html files.

How does this solution look for you, I would appreciate the feedback.