How to clip vega-lite text inside a rect? - text

In a webpage created with node/webpack, vega-lite, and vegaEmbed, I have a layer with rect marks with short annotations inside them using text marks. I'd like to clip the text to its surrounding rect but haven't figured out a way to do this and hope someone can point me in the right direction.
I realize text has a limit property in pixel units. If I could determine the pixel units of my rect marks (I don't know how to do this), using limit seems like a reasonable approach.
Also, if I knew the pixel extents of my rectangle, I can then write code to align the text within the rect which would be desirable. Currently I just use the same x as the rect, with a dx offset.
I've read about background for text which is a similar problem, but not the same.

Related

SVG Text-anchor top left

By default, the anchor for the text element in SVG is at the bottom left, but I want it to be at the top left, since I am also creating a rectangle to act as the background for the text, but it is displayed incorrectly since the text is higher than the rectangle (because rectangle anchor/offset is at the top left). Is there a way to fix this, so both text and rectangle can be drawn at same coordinates and be displayed in the same location.
The dominant-baseline property/attribute worked for me:
svg {
dominant-baseline: hanging;
}
The coordinates (x and y) you supply for text elements is used as the baseline of the text. This makes sense because if there is text with varying font sizes on the same line, you would want their baselines to line up.
There is no "automatic" way to do what you want. SVG elements are always absolutely positioned.
You will just have to move the text down a bit by making the y coordinate a bit larger.
Alternatively, you could add a dy attribute to shift the text down a bit. Or even use a transform attribute to do the same. But using either of those methods wouldn't really be simplifying the process for you.

Decreasing Polyline Stroke Width

I am trying to mimic the behavior of markers on white boards and was wondering if it I can do it with svg polylines. I know the stroke width can be set but can be it changed to vary depending on the velocity of the mouse which I can figure out or is it just a constant value for the stroke?
Or if you wanted to use SVG, instead of using a <polyline>, use a series of connected <line>s
You can't have multiple stroke widths in a single polyline element. I think canvas is probably a better fit for this task.

Can you right-align an SVG rectangle?

I'm using Raphael to draw rectangles. Whoo-hoo!
Is there a way to right align contents of an SVG file?
Not just text, but shapes as well?
I can do the math and get the computed x value, but I'm looking for the lazy-simple solution.
Thank you.
There isn't. Unlike normal web pages where the window is resized and the content flows into it, when a Raphael paper is resized, there is no sort of flow, so aligning is irrelevant. Instead of setting align=right, you just set the right edge to be the same position you set the width of the paper to be. If you enlarge the paper, you can scale the contents with a single operation. Once you've set the position of the right edge, you've essentially set the align position. You don't need to re-set all edge values when the paper changes size, you just scale everything with one command. Hope that helps

What is the proper way of drawing label in OpenGL Viewport?

I have a multiviewport OpenGL modeler application. It has three different viewports : perspective, front and top. Now I want to paint a label for each viewport and not succeeding in doing it.
What is the best way to print a label for each different perspective?
EDITED : The result
Here is the result of my attempt:
I don't understand why the perspective viewport label got scrambled like that. And, Actually I want to draw it in the upper left corner. How do I accomplished this, because I think it want 3D coordinate... is that right? Here is my code of drawing the label
glColor3f(1,0,0);
glDisable(GL_DEPTH_TEST);
glDepthMask(GL_FALSE);
glRasterPos2f(0,0);
glPushAttrib(GL_LIST_BIT); // Pushes The Display List Bits
glListBase(base - 32); // Sets The Base Character to 32
glCallLists(strlen("Perspective"), GL_UNSIGNED_BYTE, "Perspective"); // Draws The Display List Textstrlen(label)
glPopAttrib();
I use the code from here http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=13
thanks
For each viewport switch into a projection that allows you to supply "viewport space" coordinates, disable depth testing (glDisable(GL_DEPTH_TEST)) and depth writes (glDepthMask(GL_FALSE)) and draw the text using one of the methods used to draw text in OpenGL (texture mapped fonts, rendering the full text into a texture drawing that one, draw glyphs as actual geometry).
Along with #datenwolf's excellent answer, I'd add just one bit of advice: rather than drawing the label in the viewport, it's usually easier (and often looks better) to draw the label just outside the viewport. This avoids the label covering anything in the viewport, and makes it easy to get nice, cleanly anti-aliased text (which you can normally do in OpenGL as well, but it's more difficult).
If you decide you need to draw the text inside the viewport anyway, I'll add just one minor detail to what #datenwolf said: since you generally do want your text anti-aliased (even if the rest of the picture isn't) you generally want to draw the label after all the other geometry of the picture itself. If you haven't turned on anti-aliasing otherwise, you generally will want to turn it on for drawing the text.

SVG: how to position bounding box of rotated text

I have to build a SVG image containing some rotated text elements. I want to achieve the following:
Each text element shall be rotated around its center point by a degree.
The resulting (imaginary) bounding box of the rotated text shall be translated, so that it's upper left is at position x,y.
We don't know the content, i.e., the width, of the text elements beforehand.
What is the best way to do that?
(I have a basic understanding of SVG and I am able to look up the spec on my own. So I know about transform and rotate(), translate()... However, I struggle with this specific case.)

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