I am working on a graphics application and have a number of objects with captions. To put the captions, I calculate an X, Y coordinate and call:
Canvas.TextOut(XText, YText, FCaption);
I decided to use a different mapping mode to make conversions from world space to device space simpler:
SetGraphicsMode(cnv.Handle, GM_ADVANCED);
SetMapMode(pbxMain.Canvas.Handle, MM_HIENGLISH);
and now my captions are printing upside down, but still left to right.
Any thoughts on how to remedy that?
One approach I had considered was setting the map mode back to the default for outputting text, which would require some conversions to get X, Y in the different mode. Is that a reasonable tactic? Is it "correct" to change map mode during paint routines...?
Although the y axis reversed when you set MM_HIENGLISH map mode, assuming a default previous value of MM_TEXT, it doesn't cause text to be output upside-down - it just effects where it's output.
You might want to check if you're calling SetWorldTransform which is a probable cause for the problem you observe - a faulty transformation. A negative value in eM22 of the transformation structure parameter causes a reflection in the y axis.
Regarding the last part, I don't see any problem switching map modes during a single drawing task, apart from it might complicate maintaining the code.
Related
CTLineGetBoundsWithOptions() uses CTLineBoundsOptions. One of the option is kCTLineBoundsUseOpticalBounds whose doc says:
Pass this option to use optical bounds.
But I don't understand the meaning of optical bounds.
The font designer can specify the optical bounds of a glyph separately from its typographic bounds. In a TrueType font, the opbd table, if present, contains optical bounds.
From WWDC 2012 Session 226: Core Text and Fonts:
Now, as I advance to the next few slides, I want to call your attention in particular to the left and right sides of this rectangle on screen because I’m going to start passing some different options to this API and it’s going to have an effect on either side.
Let’s go ahead and advance now as I invoke use optical bounds. This is a very slight difference here, but you may have noticed that the edges of the box have been pulled in a little bit here. What’s going on here is that optical bounds are very closely related to the typographic bounds, the regular measurement of the line.
But, in this case, the font designer has specified that the way that the font is likely to be perceived by our eyes means that they don’t line up exactly with just the glyph measurements. The optical bounds in this case have been designed to pull in on either of these curly quotes here because the way our eyes see rounded shapes. It’s a bit different than the way we see straight lines, so the font designer has compensated for that by providing us information in the font.
(Find the full session transcript here.)
Microsoft describes it this way:
Aligns glyphs by their apparent left or right extents in horizontal setting, or apparent top or bottom extents in vertical setting, replacing the default behavior of aligning glyphs by their origins. Another name for this behavior would be visual justification. The optical edge of a given glyph is only indirectly related to its advance width or bounding box; this feature provides a means for getting true visual alignment.
In GeoGebra, you can easily construct scenes with the GUI and the tools available in the Graphics view. I now have two functions and created some objects around them using that tools (Their intersection point, a circle tangent to both etc.). The whole depends on 5 parameters I defined as sliders for testing.
Now I want to know the coordinates of the point. It is defined as Intersect[l, h] which doesn't help me. I can access its coordinates too (0.8, 3.98) but I want to know how to calculate them depending on the parameters. (I'd expect it to be something like (3a, 7+b-2a)). I know GeoGebra can do this because it must have done it internally to be able to draw the whole image. But I don't know how to access this information.
If you want to get the current position of a Point P you can use the x and y commands. These will update whenever the position of P changes so that you don't have to recalculate where the point should be by hand.
I've been trying to work on a small hobby project that involves plotting players' positions from a game onto a heatmap, to see where the most active areas are at various points in time.
I'm a bit new to OpenCV and its tools, but I've managed to successfully run some text matching and extraction on the scoreboard and timers in the game, now trying to take the characters' positions from the in-game minimap.
It looks like this, which is the biggest resolution image I'm able to get with (about 185x185):
I'm trying to obtain the positions of only two things: the characters (big circles) and "wards", which are represented by these icons:
So given the assets to them, I thought that because there was too much "noise" in the source image, I'd try to subtract the background of in game minimap from its image, and then try to pattern match the original character and ward image with the resulting image together (which is meant to be the minimap, minus its background). But that didn't even get close to working as you can see:
> >
Even if that did work, I wouldn't be really sure how to handle cases where the icons are partially covering each other, or how I could obtain the positions of those little ward markers.
I'd really appreciate some help, as I've been searching the Internet and banging my head for a few days and haven't gotten anywhere. I've tried a bunch of difference techniques, read guides and articles, and tried a few GUI tools to experiment with but haven't gotten any closer to a method to work this out.
Please help me with what techniques I could or should be using instead, to get the locations of all the characters and wards.
I'm not an OpenCV user, but I can speak to some general problems.
First and foremost, you goofed in subtracting the background map. It appears that you did a straight, arithmetic subtraction of the map's RGB values. For instance, the blue-team icons in the lower-left corner are roughly #99FFFF, and you're subtracting the grayish background of maybe #D0D0FF. This leaves you with #002F00, a very dark green.
Also note that you're subtracting the original map, not the part that shows. Paths beyond view are shaded, but you appear to subtract the original value.
What you need to subtract is a masked background. Unfortunately, building that mask means that you have to find the icons. Masking won't work well at this stage.
Back to the subtraction: don't just blindly subtract. Rather, look for a match in hue. When you find a hue match, simply set that pixel to 0. You have two special cases to watch: icons on the background of their own colour, especially for the blue team. In this case, you need to define the region boundaries.
Start from a pixel that's an exact match to the original background. It won't be shaded, since all such problem pixels are in plain sight of an icon. Expand from that pixel so long as you have the exact match to the original background colour. That will give you the region you can blank out.
Your next problem is to identify icons. You should now have a map with only icons, many of which are fully revealed. Those are easy matches; identify and subtract them, one key icon at a time.
You now have a map of partial icons. Switch the match algorithm: a key icon is now a match to either the exact color, or to black (indicating it was previously covered). Iterate until you have no more matches.
This does still leave you with one problem: an icon that no longer has enough pixels showing to identify. These will be icons that were either entirely covered, or covered except for a small portion that is not unique, such as a few pixels of a red circular border.
For this, a general approach is to keep track of game progress to a small extent: from an earlier time, you know where the icon used to be. Track each icon as a software object. If other icons cover it, assume it's still there until you discover otherwise.
This will handle most cases. You'll still have some problems with minions or sensors that get shot out from underneath a legend's icon, but I trust that your heat map application is not so fragile as to take modelling damage from that situation. The legend will move soon enough, revealing the small item's death. A moving minion isn't covered by a legend for long; they don't move with the same intelligence.
Does anyone know of a way to increase the number of digits displayed in ImageJ's status bar? This is normally not a problem if pixel coordinates are displayed, however once a scale is applied only two digits in the display is no longer sufficient depending on the scale factor.
ImageJ displays the coordinates of the cursor position with the help of ImagePlus#getLocationAsString(x,y), which in turn uses IJ.d2s(double n) to format the coordinates. The problem would be solved if IJ.d2s(double x, int significantDigits, int maxDigits) was used instead.
Feel free to write to the ImageJ mailing list, where Wayne Rasband (the developer of ImageJ 1.x) will likely pick it up and add the feature if he thinks it's appropriate.
As a workaround, you might want to press the alt key while moving the mouse, switching to pixel coordinates instead of calibrated coordinates in the status bar (see here).
I have a GLScene object of varying (but known) size. It is completely surrounded by a TGLDummyCube.
I want to position the GLCamera (with CameraStyle: glPerspective) so that the object is completely visible on screen. I got this running basically - the object is visible, but the distance is sometimes too far, or the object is larger than the screen and clipped.
How can I do that? I suppose that this can be done by a clever combination of camera distance and focal length, but I have not been successful so far.
This seems to be different in GLScene compared to OpenGL. I'm using GLScene and Delphi 2007.
Although varying the camera distance and focal length will change the object's visual size, it has the drawback of also changing the perspective, thus leading to a somewhat distorted view. I suggest to use the camera's SceneScale property instead.
Alas, I have no valid steps to calculate the correct value for that. In my case I have to scale to a cube with varying size, while the window size of the viewer is constant. So I placed two dummycubes at the position of the target cube, each sized to fit either the width or the height of the viewer with appropriate values for SceneScale, camera distance and FocalLength. During runtime I calculate the new SceneScale by the ratio of the target cube size in respect to the dummycube sizes. This works quite well in my case.
Edit: Here is some code I make for the calculations.
ZoomRefX and ZoomRefY are those DummyCubes
TargetDimX and TargetDimY give the size of the current object
DesignWidth and DesignHeight are the size of MyGLView at design time
DesignSceneScale is the camera's SceneScale at design time
The calculation code:
ScaleX := (ZoomRefX.CubeSize*MyGLView.Width)/(DesignWidth*TargetDimX);
ScaleY := (ZoomRefY.CubeSize*MyGLView.Height)/(DesignHeight*TargetDimY);
NewSceneScale := Min(ScaleX, ScaleY)*DesignSceneScale;
The DummyCubes ZoomRefX and ZoomRefY are sized so that they have a small margin to either the left-right or top-bottom edges of the viewing window. The are both positioned so that the front faces match. Also the target object is positioned to match its front face with those of these DummyCubes.
The formulas above allow the window size to be different from design time, but I actually didn't test this feature.
#Andreas if you've been playing with SceneScale (as you mentioned in comments) that means that you are looking for a proper way to fit object within camera view by either changing camera distance/focal length or by resizing object. If so, the easiest way to resize single object to fit the screen is to use its BoundingSphereRadius property like this:
ResizeMultiplier := 2; //play with it, it depends on your camera params
GLFreeForm1.Scale.Scale(ResizeMultiplier / GLFreeForm1.BoundingSphereRadius);
You can add GLDummyCube as root object for all other scene objects and then resize GLDummyCube with method mentioned above.