Autosizing TextView to draw on canvas

Question

I try to display some text on a PDF document. This text might be long or short but should be on a single line. This is why I opt for the TextViewCompat.setAutoSizeTextTypeWithDefaults utility method but it doesn't seem to work when drawing on a canvas. The text is cropped instead of being reduced.

Here is my code:

PageInfo startingPageInfo = new Builder(STANDARD_PDF_PAGE_WIDTH, STANDARD_PDF_PAGE_HEIGHT, 1).create();
final Page startingPage = document.startPage(startingPageInfo);

Canvas canvas = startingPage.getCanvas();
canvas.save();

final TextView documentTitle = new TextView(this);
TextViewCompat.setAutoSizeTextTypeWithDefaults(documentTitle, TextViewCompat.AUTO_SIZE_TEXT_TYPE_UNIFORM);
documentTitle.setLines(1);
documentTitle.setText(String.format("%s - %s", category.getName(), period));
documentTitle.setTextSize(TypedValue.COMPLEX_UNIT_SP, 56);
documentTitle.setTypeface(null, BOLD);
documentTitle.setTextColor(Color.BLACK);

int measuredWidth = MeasureSpec.makeMeasureSpec(canvas.getWidth() - 100, MeasureSpec.EXACTLY);
int measuredHeight = MeasureSpec.makeMeasureSpec(100, MeasureSpec.EXACTLY);
documentTitle.measure(measuredWidth, measuredHeight);
documentTitle.layout(0, 0, measuredWidth, measuredHeight); 

canvas.translate(titleDx, titleDy);
documentTitle.draw(canvas);

I'm not comfortable with custom views inside Android so I'm maybe doing something wrong here, any help would be appreciated.

Answer 1

Rewrite2+

The trouble you are having is caused by the following line:

documentTitle.layout(0, 0, measuredWidth, measuredHeight);

This line should be:

documentTitle.layout(0, 0, width, height);

Your code is setting the width and height to some astronomical values, so the text always "fits."

This is a short demo of (mostly) your code working. I used a custom LinearLayout but that won't matter. I think just the change above should work by itself, but I may have made some other little tweaks that you may find in the code below.

MyLinearLayout.java

public class MyLinearLayout extends LinearLayout {
    private AppCompatTextView documentTitle;

    public MyLinearLayout(@NonNull Context context) {
        super(context);
        init();
    }

    public MyLinearLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public MyLinearLayout(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    private void init() {
        documentTitle = new AppCompatTextView(this.getContext());
    }

    @Override
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        String displayString = String.format("%s - %s", "Some very, very, ", "very, very long text");

        int width = getWidth() - getPaddingEnd();
        int height = 100;

        ViewGroup.LayoutParams lp = new ViewGroup.LayoutParams(width, height);
        documentTitle.setLayoutParams(lp);

        TextViewCompat.setAutoSizeTextTypeWithDefaults(documentTitle, TextViewCompat.AUTO_SIZE_TEXT_TYPE_UNIFORM);
        documentTitle.setTextSize(TypedValue.COMPLEX_UNIT_SP, 56);
        documentTitle.setTypeface(null, BOLD);
        documentTitle.setTextColor(Color.BLACK);
        documentTitle.setMaxLines(1);

        int measuredWidth = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
        int measuredHeight = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
        documentTitle.measure(measuredWidth, measuredHeight);
        // Arguments here are width and height, not measureWidth and measeredHeight.
        documentTitle.layout(0, 0, width, height);

        canvas.save();
        for (int i = 0; i < 5; i++) {
            documentTitle.setText(displayString);
            documentTitle.draw(canvas);
            displayString += " - longer - longer";
            canvas.translate(0, 150);
        }
        canvas.restore();
    }

}