I want to add a plot to my first page of the (HTML5) slide. Can I achieve this in a dynamically way? Say, the background image will be generated by R code, rather than insert a semi-transparent PNG image. Thank you.
Update: What I want is
You can use the chunk option dev.args to achieve this. You will need to size the image correctly to fit your slide.
```{r dev.args = list(bg = 'transparent')}
plot(1:10, 1:10)
```
This chunk will generate a transparent png. Please read the documentation ? png to get a list of arguments you can pass. Here is one useful piece onf info from the docs.
png supports transparent backgrounds: use bg = "transparent". (Not all PNG viewers render files with transparency correctly.)
UPDATE. For plots using ggplot2, the alpha parameter can be used to control transparency.
```{r dev.args = list(bg = 'transparent'), echo = F, comment = NA, message = F}
library(ggplot2)
ggplot(mtcars, aes(wt, mpg)) +
geom_point(alpha = 0.1) +
geom_smooth(alpha = 0.1)
```
UPDATE2. To use a dynamic image as background, you need to set the background of the slide dynamically. This can be easily achieved in slidify [Disclosure: I am the author]
Here is a gist with an Rmd file which when slidified will give a transparent background.
Related
i can’t upload the segmentation image with the main image
i got the segmented image after the treatment (output test )
where the dimensions of main image and segmented are not the same
but I want to combine main image with segmented image
any solution please to match the segmentated image with the main image?
i tried to match the message displayed is "the size of segmentation image does not match with main image images must have the same dimensions"enter image description here
You can need to resample the image into the same size as the original image - assuming your segmentation is in the same origin as the input image this function should do that.
import SimpleITK as sitk
def resample_image(input_img, input_seg, is_label=False):
dimension = 3
original_spacing = itk_image.GetSpacing()
original_size = itk_image.GetSize()
resample = sitk.ResampleImageFilter()
resample.SetOutputSpacing(original_spacing)
resample.SetSize(out_size)
resample.SetOutputDirection(input_img.GetDirection())
resample.SetOutputOrigin(input_img.GetOrigin())
resample.SetTransform(sitk.Transform(dimension, sitk.sitkIdentity))
resample.SetDefaultPixelValue(input_img.GetPixelIDValue())
if is_label:
resample.SetInterpolator(sitk.sitkNearestNeighbor)
else:
resample.SetInterpolator(sitk.sitkBSpline)
return resample.Execute(itk_image)
I created a shape in mxGraph using the following options:
style[mxConstants.STYLE_SHAPE] = mxConstants.SHAPE_RECTANGLE;
style[mxConstants.STYLE_PERIMETER] = mxPerimeter.RectanglePerimeter;
style[mxConstants.STYLE_STROKECOLOR] = 'black';
style[mxConstants.STYLE_ROUNDED] = true;
style[mxConstants.STYLE_FILLCOLOR] = '#2b2b2b';
style[mxConstants.STYLE_GRADIENTCOLOR] = 'none';
If I correctly understood, in case of gradient, FILLCOLOR becomes the start-stop of it, and GRADIENTCOLOR the end-stop, but it's generated via SVG at first rendering.
I'd need to create a gradient AFTER first rendeting, in real-time, to mimic a progress-bar (like copy files process in Windows that color icon in Application Bar).
How to add (edit) gradient color in real-time?
Before I start, let me say that I'm a complete beginner at Pygame.
Here's my current program:
import pygame, sys, random
pygame.init()
white = ((255,255,255))
display_width = 800
display_height = 600
FPS = 15
gameDisplay = pygame.display.set_mode((display_width, display_height))
pygame.display.set_caption('Francis')
gameExit = False
lead_x = display_width/2
lead_y = display_height/2
lead_x_change = 0
lead_y_change = 0
clock = pygame.time.Clock()
while not gameExit:
for event in pygame.event.get():
if event.type== pygame.QUIT:
gameExit = True
francis = pygame.sprite.Sprite() #create sprite
francis.image = pygame.image.load("francis.png").convert() #load francis image
francis.rect = francis.image.get_rect() # use image extent values
francis.rect.center = [lead_x,lead_y]
gameDisplay.fill(white)
gameDisplay.blit(francis.image, francis.rect)
pygame.display.update()
clock.tick(FPS)
pygame.quit()
quit()
What I plan to do with this program is load in my sprite (francis) and use the arrow keys to move him across the screen. I plan to create that motion by having each arrow key pressed add or subtract 10 pixels from lead_x, which should be the sprite's x location. I'm not sure whether the code I used to load in the sprite is correct. I used "francis.rect.center" then gave the coordinates to that. Is there a better way to load and position a sprite?
Also, my sprite has a black rectangle around it whenever I load it. The sprite itself is a 30x70 picture. Where there is not a pixel of the actual person, I just have transparency. The transparency works fine, but whenever I load in the image, there's a black rectangle around the border of the sprite. I have a feeling this has to do with the way I loaded in the sprite, but I'd appreciate if you'd let me know. (I've tried converting it to png, bmp, and jpg. png and bmp both have black borders, and jpg has black background instead of transparency)
Any and all help is appreciated!
When you do your image load with
francis.image = pygame.image.load("francis.png").convert() #load francis image
you should do
francis.image = pygame.image.load("francis.png").convert_alpha() #load francis image
as png images have an alpha channel which is the transparent part of the image. If you don't know what this means load your image into an image editor and remove the part you do not need by selecting the and deleting them. Now these parts will contain no colour information and therefor will be the alpha channel for the image.
You can also set the colour key of the image by
francis.image.set_colorkey(0, RLEACCEL) # the colour key is set to 0
A key colour is also transparent. (That's how they shoot movies like spiderman, fantastic four etc. :-))
read this too
https://www.pygame.org/docs/ref/surface.html#pygame.Surface.set_alpha.
hope this helps.
Regarding how you position sprites, I believe the norm is to go by the top-left, but I don't think it matters much.
Try opening the picture in paint and saving it as a gif. Note of course that changing the file extension doesn't make a difference by renaming it, it is actually still the same file type. So to change a file type, you have to use the "save as" option and select a file type. Try using a gif or a png using this method assuming you haven't so far.
francis.rect.center = [lead_x,lead_y]
You set it as a list. I'm pretty sure it's meant to be a tuple i.e.
francis.rect.center = (lead_x,lead_y)
What does the ".convert" part do in "francis.image = pygame.image.load("francis.png").convert()"
I'm pretty sure it's not meant to be there, try removing it unless you specifically know you need it.
You forgot a crucial line in your code. On the end of the mainloop you should be saying the following line;
pygame.display.flip()
This has something to do with how it loads the pixels from top to bottom or something, I honestly don't know, but I'm pretty sure you need it otherwise the program wont work. I think it replaces pygame.display.update()
Let's say that I use some HTML5 markup:
<canvas id="e" width="400" height="200"></canvas>
<script>
var canvas = document.getElementById("e");
var context = canvas.getContext("2d");
context.fillStyle = "red";
context.font = "bold 72px JerseyLetters";
context.fillText("Bulls", 50, 100);
</script>
To make some cool text like this:
Then I decide I want these letters to fit into an envelope that looks like this:
Hoping to get something like this:
How would I go about (1) defining an envelope like the one above and then (2) putting the text in the envelope using HTML5 Canvas to get the result?
I am open to either something that directly places text in the envelope or a solution that first creates an image and then fits the image in an envelope.
Thanks!
EDIT
I added the tags "webgl" and "three.js" to this question on the advice of #markE. I will research those two packages in the mean time as well. I'm very new to .
webGL way:
Do it as a image-processing with pixel-shader.
Render text with 2d canvas, bind webGL texture with buffer and fill texture with canvas image (rendered text). Have prepared envelope that actually maps the area that envelope holds and also every pixel play role of the UV coordinate from the first image. Running that as pixel shader, you have image-to-be-squeezed and envelope (uvs) you'll output final image. That way, it's completely font and text independent. You could even probably make one image-processing step more so you could load any envelope shape and process it on spot, so it becomes font, text and envelope-shape independent.
I'm not sure how well did I explain this.
Hope this helps, though.
SVG provides these sort of text transforms. See http://tavmjong.free.fr/SVG/TEXT_PATH/TextPath.html
EDIT: This link appears to be converting the text to actual SVG. Probably not going to be helpful for you, sorry.
I want to use canvas to dynamically alter the transparency index of images, is this possible?
There are several ways depending on what you want to accomplish.
Firstly if you just want to display an image with a color for the transparency, you don't need canvas. You can just add CSS styling to the image:
<img src="theURL" style="background-color: red;">
Lets say you do want canvas though. The most efficient way is to just draw the color first and then the image.
Another way is to draw the image to the canvas, set the globalcompositeOperateion to 'destination-over' and then fill the area of the image with the color you want.
ctx.drawImage(img,0,0);
ctx.globalCompositeOperation = 'destination-over'
ctx.fillStyle = 'blue';
ctx.fillRect(0,0,280,210); // if the width and height are 280x210
See it in action here, replacing a transparent background with blue:
http://jsfiddle.net/MEHbr/327/
I would advise against using getImageData and putImageData unless you need the fine per-pixel control, as they are much slower.
For saving the image, canvas2Image has the best options:
http://www.nihilogic.dk/labs/canvas2image/
Yes it is possible you have to use getImageData and putImagaData
Reference
imageData = canvasContext.getImageData( 0, 0, canvasContext.canvas.width, canvasContext.canvas.height );
for( i = 0; i < imageData.length; i+= 4 ) {
imageData[i+3] = opacityValue;
}
canvasContext.putImageData(imageData, 0, 0 );
Heres an example that does what your looking for, (also what the above snippet was taken from)
http://labs.josh-ho.com/getImageData/
You can create a new class for your canvas and create css to style it:
.canvas_class{
-moz-opacity:0.5; /* For older FF versions */
-khtml-opacity:0.5;
opacity:0.5;
}
You can then use the jQuery library to modify the DOM live:
http://api.jquery.com/attr/
I hope this helps you add changeable transparency to your canvases :D